diff --git a/app/assets/stylesheets/application.scss b/app/assets/stylesheets/application.scss
index 71cbed7d0..3af1249cd 100644
--- a/app/assets/stylesheets/application.scss
+++ b/app/assets/stylesheets/application.scss
@@ -23,6 +23,7 @@
 $primary: $dark-codebar-blue !default;
 
 @import "bootstrap-custom";
+@import "partials/activity_strip";
 
 /* Bootstrap's Reboot sets legends to float: left, which puts the first check box in a fieldset off to the
    right instead of underneath the legend. This overrides that. */
diff --git a/app/assets/stylesheets/partials/_activity_strip.scss b/app/assets/stylesheets/partials/_activity_strip.scss
new file mode 100644
index 000000000..5fac96ec5
--- /dev/null
+++ b/app/assets/stylesheets/partials/_activity_strip.scss
@@ -0,0 +1,8 @@
+// app/assets/stylesheets/partials/_activity_strip.scss
+.activity-strip {
+  .activity-cell {
+    &-empty { fill: $gray-200; }
+    &-login_only { fill: $gray-400; }
+    &-active { fill: $codebar-blue; }
+  }
+}
diff --git a/app/components/admin/members/activity_strip_component.html.erb b/app/components/admin/members/activity_strip_component.html.erb
new file mode 100644
index 000000000..a014b5e7c
--- /dev/null
+++ b/app/components/admin/members/activity_strip_component.html.erb
@@ -0,0 +1,15 @@
+<%# app/components/admin/members/activity_strip_component.html.erb %>
+<div class="activity-strip">
+  <h5>Activity — last 12 months</h5>
+  <svg viewBox="0 0 <%= svg_width %> 32" width="100%" height="32"
+       role="img" aria-label="Weekly activity, last 12 months">
+    <% weeks.each_with_index do |week, i| %>
+      <rect x="<%= i * (CELL_WIDTH + CELL_GAP) %>" y="0"
+            width="<%= CELL_WIDTH %>" height="32" rx="2"
+            class="activity-cell activity-cell-<%= week.state %>"
+            aria-label="<%= iso_week(week) %>">
+        <title><%= title_for(week) %></title>
+      </rect>
+    <% end %>
+  </svg>
+</div>
diff --git a/app/components/admin/members/activity_strip_component.rb b/app/components/admin/members/activity_strip_component.rb
new file mode 100644
index 000000000..f2a0f4e6d
--- /dev/null
+++ b/app/components/admin/members/activity_strip_component.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+module Admin
+  module Members
+    class ActivityStripComponent < ViewComponent::Base
+      CELL_WIDTH = 8
+      CELL_GAP = 4
+
+      def initialize(weeks:)
+        super()
+        @weeks = weeks
+      end
+
+      private
+
+      attr_reader :weeks
+
+      def title_for(week)
+        summary = week.counts.map { |key, count| "#{count} #{key.tr('.', ' ').humanize}" }.join(', ')
+        "#{iso_week(week)} (week of #{week.week_start.strftime('%-d %b %Y')}): #{summary.presence || 'no activity'}"
+      end
+
+      def iso_week(week)
+        week.week_start.strftime('%G-W%V')
+      end
+
+      def svg_width
+        weeks.size * (CELL_WIDTH + CELL_GAP)
+      end
+    end
+  end
+end
diff --git a/app/controllers/admin/members_controller.rb b/app/controllers/admin/members_controller.rb
index a649f6815..16d511508 100644
--- a/app/controllers/admin/members_controller.rb
+++ b/app/controllers/admin/members_controller.rb
@@ -24,9 +24,11 @@ def search
   end
 
   def show
-    @member = MemberPresenter.new(Member.find(params[:id]))
+    member = Member.find(params[:id])
+    @member = MemberPresenter.new(member)
     load_attendance_data(@member)
-
+    @activity_weeks = Admin::Members::ActivityStrip.new(member).rows
+    @activities = PublicActivity::Activity.where(owner: member).order(created_at: :desc).limit(30)
     @actions = admin_actions(@member).sort_by(&:created_at).reverse
   end
 
diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 72c890099..34cb23bc0 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -60,6 +60,25 @@ def sponsorship_level_title(level)
     "#{level.humanize} sponsors"
   end
 
+  # Admin-page subject of a member activity: the entity the action was about.
+  # Returns nil when the subject is the member themselves (e.g. logins, bans).
+  def activity_subject(activity)
+    case (trackable = activity.trackable)
+    when WorkshopInvitation then trackable.workshop
+    when Invitation then trackable.event
+    when MeetingInvitation then trackable.meeting
+    when Member then nil
+    else trackable
+    end
+  end
+
+  def activity_subject_label(subject)
+    return "#{subject.chapter.name} #{subject.name}" if subject.is_a?(Group)
+    return subject.full_name if subject.respond_to?(:full_name)
+
+    subject.try(:name) || subject.to_s
+  end
+
   private
 
   def humanize_date_with_time(datetime, end_time)
diff --git a/app/services/admin/members/activity_strip.rb b/app/services/admin/members/activity_strip.rb
new file mode 100644
index 000000000..6adfbe5e8
--- /dev/null
+++ b/app/services/admin/members/activity_strip.rb
@@ -0,0 +1,57 @@
+# frozen_string_literal: true
+
+module Admin
+  module Members
+    # Buckets a member's activity log into the 52 ISO weeks ending the current week.
+    # Sole owner of strip state classification; the component renders, never classifies.
+    class ActivityStrip
+      WEEK_COUNT = 52
+      LOGIN_ONLY_KEYS = %w[member.login member.logout].freeze
+
+      Row = Data.define(:week_start, :state, :counts)
+
+      def initialize(member, now: Time.zone.now)
+        @member = member
+        @now = now
+      end
+
+      def rows # rubocop:disable Metrics/AbcSize, Metrics/MethodLength
+        activities = PublicActivity::Activity
+                     .where(owner: @member)
+                     .where(created_at: window_start..@now)
+                     .order(:created_at)
+
+        grouped = activities.group_by { |a| a.created_at.to_date.beginning_of_week.beginning_of_day }
+
+        weeks.map do |week_start|
+          week_activities = grouped[week_start] || []
+          counts = week_activities.map(&:key).tally
+          state = classify(counts)
+
+          Row.new(week_start:, state:, counts:)
+        end
+      end
+
+      private
+
+      def classify(counts)
+        return :empty if counts.empty?
+        return :login_only if counts.keys.all? { |key| LOGIN_ONLY_KEYS.include?(key) }
+
+        :active
+      end
+
+      def weeks
+        @weeks ||= Array.new(WEEK_COUNT) { |i| current_week_start - (WEEK_COUNT - 1 - i).weeks }
+      end
+
+      def window_start
+        @window_start ||= current_week_start - (WEEK_COUNT - 1).weeks
+      end
+
+      def current_week_start
+        @current_week_start ||= @now.to_date.beginning_of_week.beginning_of_day
+      end
+    end
+  end
+end
diff --git a/app/views/admin/members/show.html.haml b/app/views/admin/members/show.html.haml
index d9c25b0cb..e98021b17 100644
--- a/app/views/admin/members/show.html.haml
+++ b/app/views/admin/members/show.html.haml
@@ -29,3 +29,25 @@
       .row.mt-4
         .col
           = link_to 'View all RSVPS', admin_member_events_path(@member), class: 'btn btn-primary btn-block'
+
+      .row.mt-4
+        .col
+          %h3.mt-4 Activity
+          = render Admin::Members::ActivityStripComponent.new(weeks: @activity_weeks)
+
+          %ul.list-unstyled.activity-log.mt-3
+            - @activities.group_by { |a| a.created_at.beginning_of_week.to_date }.each do |week_start, activities|
+              %li
+                %h5.mt-3
+                  #{week_start.strftime('%G-W%V')}
+                  %span.small.text-muted (week of #{week_start.strftime('%-d %b %Y')})
+                %ul.list-unstyled
+                  - activities.each do |activity|
+                    %li.pb-2.mb-2
+                      = activity.key.tr('.', ' ').humanize
+                      - if (subject = activity_subject(activity))
+                        %span.text-muted.ms-1
+                          = t('admin.members.activity.for', subject: link_to(activity_subject_label(subject), [:admin, subject])).html_safe
+                      %span.text-muted.ms-2= l(activity.created_at, format: :activity_log)
+            - if @activities.empty?
+              %li.text-muted No recorded activity yet
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 9cd7385de..729d2b661 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -59,6 +59,7 @@ en:
       full_date: "%d %B %Y"
       default_date: "%d/%m/%Y"
       website_format: "%a, %d %B %Y at %H:%M"
+      activity_log: "%A, %Y-%m-%d %H:%M"
       day_in_words: "%a"
       day: "%d"
       month: "%B"
@@ -658,6 +659,9 @@ en:
   admin:
     dashboard:
       title: "Admin"
+    members:
+      activity:
+        for: "for %{subject}"
     workshop:
       manage_rsvps:
         text: "RSVP Students and Coaches to the workshop. The attendance confirmation email will be triggered and they will be removed from the waiting list."
diff --git a/spec/components/admin/members/activity_strip_component_spec.rb b/spec/components/admin/members/activity_strip_component_spec.rb
new file mode 100644
index 000000000..37891aaec
--- /dev/null
+++ b/spec/components/admin/members/activity_strip_component_spec.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe Admin::Members::ActivityStripComponent do
+  let(:member) { Fabricate(:member) }
+  let(:now) { Time.zone.local(2026, 9, 2, 12, 0, 0) }
+  let(:rows) do
+    Admin::Members::ActivityStrip.new(member, now:).tap do |_strip|
+      PublicActivity::Activity.create!(
+        owner: member, trackable: member, key: 'member.login',
+        created_at: now - 1.week, updated_at: now - 1.week
+      )
+      PublicActivity::Activity.create!(
+        owner: member, trackable: member, key: 'event_invitation.rsvp',
+        created_at: now - 2.weeks, updated_at: now - 2.weeks
+      )
+    end.rows
+  end
+
+  before { render_inline(described_class.new(weeks: rows)) }
+
+  it 'renders 52 cells' do
+    expect(page).to have_css('rect', count: 52)
+  end
+
+  it 'renders all three state classes' do
+    expect(page).to have_css('.activity-cell-empty')
+    expect(page).to have_css('.activity-cell-login_only')
+    expect(page).to have_css('.activity-cell-active')
+  end
+
+  it 'renders a tooltip with the week and counts' do
+    expect(page).to have_css('rect title', text: 'Event invitation rsvp')
+  end
+
+  it 'labels each cell with its ISO week' do
+    expect(page).to have_css('rect[aria-label]', count: 52)
+    expect(page).to have_css("rect[aria-label='#{(now - 2.weeks).to_date.beginning_of_week.strftime('%G-W%V')}']")
+    expect(page).to have_css('rect title', text: /^2026-W/)
+  end
+end
diff --git a/spec/controllers/admin/members_controller_spec.rb b/spec/controllers/admin/members_controller_spec.rb
index a3f2182bc..3b3267b8a 100644
--- a/spec/controllers/admin/members_controller_spec.rb
+++ b/spec/controllers/admin/members_controller_spec.rb
@@ -112,6 +112,68 @@
     end
   end
 
+  describe 'GET #show' do
+    let(:admin) { Fabricate(:member) }
+    let(:chapter) { Fabricate(:chapter) }
+
+    before do
+      admin.add_role(:admin)
+      login_as_admin(admin)
+    end
+
+    describe 'activity strip' do
+      render_views
+
+      it 'renders the strip for any member' do
+        member = Fabricate(:member)
+
+        get :show, params: { id: member.id }
+
+        expect(response.body).to include('activity-strip')
+      end
+    end
+
+    describe 'activity log' do
+      render_views
+
+      let(:member) { Fabricate(:member) }
+
+      it 'shows the latest 30 activities for any member' do
+        30.times do |i|
+          MemberActivityRecorder.record(actor: member, key: 'member.login',
+                                        trackable: member)
+          PublicActivity::Activity.last.update!(created_at: i.days.ago)
+        end
+        MemberActivityRecorder.record(actor: member, key: 'member.logout', trackable: member)
+        PublicActivity::Activity.last.update!(created_at: 31.days.ago)
+
+        get :show, params: { id: member.id }
+
+        within('.activity-log') do
+          expect(page).to have_text('Member login')
+          expect(page).to have_no_text('Member logout')
+          expect(page).to have_no_text('No recorded activity')
+        end
+      end
+
+      it 'shows an empty state for members without activity' do
+        get :show, params: { id: member.id }
+
+        expect(response.body).to include('No recorded activity yet')
+      end
+
+      it 'links to the related entity of an activity' do
+        invitation = Fabricate(:invitation)
+        MemberActivityRecorder.record(actor: invitation.member, key: 'event_invitation.rsvp',
+                                      trackable: invitation)
+
+        get :show, params: { id: invitation.member.id }
+
+        expect(response.body).to include("href=\"#{admin_event_path(invitation.event)}\"")
+      end
+    end
+  end
+
   describe 'GET #send_eligibility_email' do
     let(:member) { Fabricate(:member) }
     let(:admin) { Fabricate(:member) }
diff --git a/spec/services/admin/members/activity_strip_spec.rb b/spec/services/admin/members/activity_strip_spec.rb
new file mode 100644
index 000000000..e6af6df0f
--- /dev/null
+++ b/spec/services/admin/members/activity_strip_spec.rb
@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe Admin::Members::ActivityStrip do
+  let(:member) { Fabricate(:member) }
+  let(:now) { Time.zone.local(2026, 9, 2, 12, 0, 0) } # Wednesday, current week starts Mon 31 Aug
+  let(:strip) { described_class.new(member, now:) }
+
+  def activity_at(time, key: 'member.login')
+    PublicActivity::Activity.create!(owner: member, key:, trackable: member,
+                                     created_at: time, updated_at: time)
+  end
+
+  it 'returns 52 rows oldest first' do
+    rows = strip.rows
+
+    expect(rows.size).to eq(52)
+    expect(rows.first.week_start).to eq(Time.zone.local(2025, 9, 8))
+    expect(rows.last.week_start).to eq(Time.zone.local(2026, 8, 31))
+  end
+
+  it 'marks weeks with no rows as empty' do
+    expect(strip.rows.map(&:state)).to all(eq(:empty))
+  end
+
+  it 'marks login-only weeks as login_only' do
+    activity_at(now - 2.weeks, key: 'member.login')
+
+    expect(strip.rows[-3].state).to eq(:login_only)
+  end
+
+  it 'marks weeks with any non-login key as active' do
+    activity_at(now - 2.weeks, key: 'event_invitation.rsvp')
+
+    expect(strip.rows[-3].state).to eq(:active)
+  end
+
+  it 'counts keys for tooltips' do
+    activity_at(now - 1.week, key: 'member.login')
+    activity_at(now - 1.week, key: 'event_invitation.rsvp')
+
+    expect(strip.rows[-2].counts).to eq('member.login' => 1, 'event_invitation.rsvp' => 1)
+  end
+
+  it 'buckets by ISO week with the boundary at window start' do
+    activity_at(strip.rows.first.week_start) # exactly at the window edge
+    activity_at(strip.rows.first.week_start - 1.second) # one second before: outside
+
+    expect(strip.rows.first.state).to eq(:login_only)
+  end
+end