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..5c823ce8c
--- /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-pink; }
+  }
+}
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..951769206
--- /dev/null
+++ b/app/components/admin/members/activity_strip_component.html.erb
@@ -0,0 +1,13 @@
+<%# 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 %>"
+            title="<%= title_for(week) %>" />
+    <% 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..380b78f16
--- /dev/null
+++ b/app/components/admin/members/activity_strip_component.rb
@@ -0,0 +1,28 @@
+# 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('.', ' ')}" }.join(', ')
+        "Week of #{week.week_start.strftime('%-d %b %Y')}: #{summary.presence || 'no activity'}"
+      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..4317ed31d 100644
--- a/app/controllers/admin/members_controller.rb
+++ b/app/controllers/admin/members_controller.rb
@@ -24,9 +24,10 @@ 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
     @actions = admin_actions(@member).sort_by(&:created_at).reverse
   end
 
diff --git a/app/services/admin/members/activity_strip.rb b/app/services/admin/members/activity_strip.rb
new file mode 100644
index 000000000..9feacca6b
--- /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 = Struct.new(:week_start, :state, :counts, keyword_init: true)
+
+      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/_profile.html.haml b/app/views/admin/members/_profile.html.haml
index 8b6061ee6..3e1725817 100644
--- a/app/views/admin/members/_profile.html.haml
+++ b/app/views/admin/members/_profile.html.haml
@@ -6,6 +6,9 @@
   %span.d-block
     %p.lead= @member.about_you
 
+  - if @member.organiser?
+    = render Admin::Members::ActivityStripComponent.new(weeks: @activity_weeks)
+
   - if @member.skills.any?
     .mb-4
       %h5 Skills
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..172076879
--- /dev/null
+++ b/spec/components/admin/members/activity_strip_component_spec.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe Admin::Members::ActivityStripComponent, type: :component 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*="event_invitation rsvp"]')
+  end
+end
diff --git a/spec/controllers/admin/members_controller_spec.rb b/spec/controllers/admin/members_controller_spec.rb
index 05e96c118..14fc9f84e 100644
--- a/spec/controllers/admin/members_controller_spec.rb
+++ b/spec/controllers/admin/members_controller_spec.rb
@@ -112,47 +112,79 @@
     end
   end
 
-  describe 'GET #send_eligibility_email' do
-    let(:member) { Fabricate(:member) }
-    let(:admin) { Fabricate(:member) }
+  describe 'GET #show' do
+  let(:admin) { Fabricate(:member) }
+  let(:chapter) { Fabricate(:chapter) }
 
-    before do
-      admin.add_role(:admin)
-      login_as_admin(admin)
-    end
+  before do
+    admin.add_role(:admin)
+    login_as_admin(admin)
+  end
 
-    it 'creates an eligibility inquiry' do
-      expect do
-        get :send_eligibility_email, params: { member_id: member.id }
-      end.to change(EligibilityInquiry, :count).by(1)
-    end
+  describe 'activity strip' do
+    render_views
 
-    it 'sends an eligibility check email' do
-      mailer = double(deliver_now: true)
-      allow(MemberMailer).to receive(:eligibility_check)
-        .with(member, member.email)
-        .and_return(mailer)
+    let(:organiser) { Fabricate(:member) }
 
-      get :send_eligibility_email, params: { member_id: member.id }
+    before { organiser.add_role(:organiser, chapter) }
 
-      expect(MemberMailer).to have_received(:eligibility_check)
-        .with(member, member.email)
+    it 'renders the strip for organisers' do
+      get :show, params: { id: organiser.id }
+
+      expect(response.body).to include('activity-strip')
     end
 
-    it 'redirects to the member page' do
-      get :send_eligibility_email, params: { member_id: member.id }
+    it 'does not render the strip for non-organisers' do
+      plain = Fabricate(:member)
 
-      expect(response).to redirect_to([:admin, member])
+      get :show, params: { id: plain.id }
+
+      expect(response.body).not_to include('activity-strip')
     end
+  end
+  end
 
-    context 'when not authenticated' do
-      before { login(Fabricate(:member)) }
+  describe 'GET #send_eligibility_email' do
+      let(:member) { Fabricate(:member) }
+      let(:admin) { Fabricate(:member) }
+
+      before do
+        admin.add_role(:admin)
+        login_as_admin(admin)
+      end
+
+      it 'creates an eligibility inquiry' do
+        expect do
+          get :send_eligibility_email, params: { member_id: member.id }
+        end.to change(EligibilityInquiry, :count).by(1)
+      end
+
+      it 'sends an eligibility check email' do
+        mailer = double(deliver_now: true)
+        allow(MemberMailer).to receive(:eligibility_check)
+          .with(member, member.email)
+          .and_return(mailer)
 
-      it 'redirects to login' do
         get :send_eligibility_email, params: { member_id: member.id }
 
-        expect(response).to have_http_status(:found)
+        expect(MemberMailer).to have_received(:eligibility_check)
+          .with(member, member.email)
+      end
+
+      it 'redirects to the member page' do
+        get :send_eligibility_email, params: { member_id: member.id }
+
+        expect(response).to redirect_to([:admin, member])
+      end
+
+      context 'when not authenticated' do
+        before { login(Fabricate(:member)) }
+
+        it 'redirects to login' do
+          get :send_eligibility_email, params: { member_id: member.id }
+
+          expect(response).to have_http_status(:found)
+        end
       end
-    end
   end
 end
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