diff --git a/.github/workflows/prod-build-deploy.yml b/.github/workflows/prod-build-deploy.yml
index c1483d4ed7..e79204d34e 100644
--- a/.github/workflows/prod-build-deploy.yml
+++ b/.github/workflows/prod-build-deploy.yml
@@ -247,7 +247,7 @@ jobs:
               throw error
             }
 
-      - name: Send Slack notification if workflow fails
+      - name: Send Slack notification if workflow failed
         uses: someimportantcompany/github-actions-slack-message@0b470c14b39da4260ed9e3f9a4f1298a74ccdefd
         if: ${{ failure() }}
         with:
diff --git a/.github/workflows/staging-build-pr.yml b/.github/workflows/staging-build-pr.yml
index 9263188b36..5d4f970743 100644
--- a/.github/workflows/staging-build-pr.yml
+++ b/.github/workflows/staging-build-pr.yml
@@ -14,6 +14,11 @@ on:
 permissions:
   contents: read
 
+# This allows one Build workflow run to interrupt another
+concurrency:
+  group: '${{ github.workflow }} @ ${{ github.event.pull_request.head.label }}'
+  cancel-in-progress: true
+
 jobs:
   debug:
     runs-on: ubuntu-latest
@@ -27,8 +32,10 @@ jobs:
     if: ${{ github.repository == 'github/docs-internal' || github.repository == 'github/docs' }}
     runs-on: ubuntu-latest
     timeout-minutes: 5
+    # This interrupts Build, Deploy, and pre-write Undeploy workflow runs in
+    # progress for this PR branch.
     concurrency:
-      group: staging_${{ github.head_ref }}
+      group: 'PR Staging @ ${{ github.event.pull_request.head.label }}'
       cancel-in-progress: true
     steps:
       - name: Check out repo
diff --git a/.github/workflows/staging-deploy-pr.yml b/.github/workflows/staging-deploy-pr.yml
index 7e59ff4c2b..db611d66e9 100644
--- a/.github/workflows/staging-deploy-pr.yml
+++ b/.github/workflows/staging-deploy-pr.yml
@@ -18,6 +18,15 @@ permissions:
   pull-requests: read
   statuses: write
 
+# IMPORTANT: Intentionally OMIT a `concurrency` configuration from this workflow's
+# top-level as we do not have any guarantee of identifying values being available
+# within the `github.event` context for PRs from forked repos!
+#
+# The implication of this shortcoming is that we may have multiple workflow runs
+# of this running at the same time for different commits within the same PR.
+# However, once they reach the `concurrency` configurations deeper down within
+# this workflow's jobs, then we can expect concurrent short-circuiting to begin.
+
 env:
   CONTEXT_NAME: '${{ github.workflow }} / deploy (${{ github.event.workflow_run.event }})'
   ACTIONS_RUN_LOG: https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}
@@ -183,9 +192,12 @@ jobs:
         (github.repository == 'github/docs-internal' || github.repository == 'github/docs')
       }}
     runs-on: ubuntu-latest
-    timeout-minutes: 1
+    # This timeout should match or exceed the value of the timeout for Undeploy
+    timeout-minutes: 5
+    # This interrupts Build, Deploy, and pre-write Undeploy workflow runs in
+    # progress for this PR branch.
     concurrency:
-      group: 'staging_${{ needs.pr-metadata.outputs.head_ref }}'
+      group: 'PR Staging @ ${{ needs.pr-metadata.outputs.head_label }}'
       cancel-in-progress: true
     outputs:
       pull_request_state: ${{ steps.check-pr.outputs.state }}
@@ -197,12 +209,33 @@ jobs:
           PR_NUMBER: ${{ needs.pr-metadata.outputs.number }}
         with:
           script: |
+            const sleep = require('await-sleep') // Does not require ESM
+
+            const blockingLabel = 'automated-block-deploy'
             const { owner, repo } = context.repo
-            const { data: pullRequest } = await github.pulls.get({
-              owner,
-              repo,
-              pull_number: process.env.PR_NUMBER
-            })
+            const startTime = Date.now()
+
+            let pullRequest = {}
+            let blocked = true
+
+            // Keep polling the PR until the blocking label has been removed
+            while (blocked) {
+              const { data: pr } = await github.pulls.get({
+                owner,
+                repo,
+                pull_number: process.env.PR_NUMBER
+              })
+
+              blocked = pr.labels.some(({ name }) => name === blockingLabel)
+              if (blocked) {
+                console.warn(`WARNING! PR currently has blocking label "${blockingLabel}" (after ${Date.now() - startTime} ms). Will check again soon...`)
+                await sleep(15000) // Wait 15 seconds and check again
+              } else {
+                console.log(`PR was unblocked (after ${Date.now() - startTime} ms)!`)
+                pullRequest = pr
+              }
+            }
+
             core.setOutput('state', pullRequest.state)
 
   prepare-for-deploy:
@@ -210,8 +243,10 @@ jobs:
     if: ${{ needs.check-pr-before-prepare.outputs.pull_request_state == 'open' }}
     runs-on: ubuntu-latest
     timeout-minutes: 5
+    # This interrupts Build, Deploy, and pre-write Undeploy workflow runs in
+    # progress for this PR branch.
     concurrency:
-      group: 'staging_${{ needs.pr-metadata.outputs.head_ref }}'
+      group: 'PR Staging @ ${{ needs.pr-metadata.outputs.head_label }}'
       cancel-in-progress: true
     outputs:
       source_blob_url: ${{ steps.build-source.outputs.download_url }}
@@ -361,7 +396,7 @@ jobs:
               target_url: ACTIONS_RUN_LOG
             })
 
-      - name: Send Slack notification if workflow fails
+      - name: Send Slack notification if deployment preparation job failed
         uses: someimportantcompany/github-actions-slack-message@0b470c14b39da4260ed9e3f9a4f1298a74ccdefd
         if: ${{ failure() }}
         with:
@@ -374,8 +409,10 @@ jobs:
     needs: [pr-metadata, prepare-for-deploy]
     runs-on: ubuntu-latest
     timeout-minutes: 1
+    # This interrupts Build, Deploy, and pre-write Undeploy workflow runs in
+    # progress for this PR branch.
     concurrency:
-      group: 'staging_${{ needs.pr-metadata.outputs.head_ref }}'
+      group: 'PR Staging @ ${{ needs.pr-metadata.outputs.head_label }}'
       cancel-in-progress: true
     outputs:
       pull_request_state: ${{ steps.check-pr.outputs.state }}
@@ -400,8 +437,10 @@ jobs:
     if: ${{ needs.check-pr-before-deploy.outputs.pull_request_state == 'open' }}
     runs-on: ubuntu-latest
     timeout-minutes: 10
+    # This interrupts Build, Deploy, and pre-write Undeploy workflow runs in
+    # progress for this PR branch.
     concurrency:
-      group: 'staging_${{ needs.pr-metadata.outputs.head_ref }}'
+      group: 'PR Staging @ ${{ needs.pr-metadata.outputs.head_label }}'
       cancel-in-progress: true
     steps:
       - name: Check out repo's default branch
@@ -548,7 +587,7 @@ jobs:
               target_url: ACTIONS_RUN_LOG
             })
 
-      - name: Send Slack notification if workflow fails
+      - name: Send Slack notification if deployment job failed
         uses: someimportantcompany/github-actions-slack-message@0b470c14b39da4260ed9e3f9a4f1298a74ccdefd
         if: ${{ failure() }}
         with:
diff --git a/.github/workflows/staging-undeploy-pr.yml b/.github/workflows/staging-undeploy-pr.yml
index 39d6957628..e71e363f1f 100644
--- a/.github/workflows/staging-undeploy-pr.yml
+++ b/.github/workflows/staging-undeploy-pr.yml
@@ -13,6 +13,11 @@ permissions:
   contents: read
   deployments: write
 
+# This prevents one Undeploy workflow run from interrupting another
+concurrency:
+  group: '${{ github.workflow }} @ ${{ github.event.pull_request.head.label }}'
+  cancel-in-progress: false
+
 jobs:
   debug:
     runs-on: ubuntu-latest
@@ -22,15 +27,33 @@ jobs:
           GITHUB_CONTEXT: ${{ toJSON(github) }}
         run: echo "$GITHUB_CONTEXT"
 
-  undeploy:
+  cancel-jobs-before-undeploy:
     if: ${{ github.repository == 'github/docs-internal' || github.repository == 'github/docs' }}
-    name: Undeploy
     runs-on: ubuntu-latest
-    timeout-minutes: 2
+    # This interrupts Build and Deploy workflow runs in progress for this PR
+    # branch. However, it does so with an intentionally short, independent job
+    # so that the following `undeploy` job cannot be cancelled once started!
     concurrency:
-      group: staging_${{ github.head_ref }}
+      group: 'PR Staging @ ${{ github.event.pull_request.head.label }}'
       cancel-in-progress: true
     steps:
+      - name: Cancelling other deployments via concurrency configuration
+        run: |
+          echo 'Cancelling other deployment runs (if any)...'
+
+  undeploy:
+    if: ${{ github.repository == 'github/docs-internal' || github.repository == 'github/docs' }}
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    # IMPORTANT: Intentionally OMIT a `concurrency` configuration from this job!
+    steps:
+      - name: Add a label to the PR to block deployment during undeployment
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          PR_NUMBER: ${{ github.event.pull_request.number }}
+        run: |
+          gh pr edit $PR_NUMBER --add-label "automated-block-deploy"
+
       - name: Check out repo's default branch
         uses: actions/checkout@5a4ac9002d0be2fb38bd78e4b4dbde5606d7042f
         with:
@@ -91,3 +114,20 @@ jobs:
               console.error(error)
               throw error
             }
+
+      - if: ${{ always() }}
+        name: Remove the label from the PR to unblock deployment
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          PR_NUMBER: ${{ github.event.pull_request.number }}
+        run: |
+          gh pr edit $PR_NUMBER --remove-label "automated-block-deploy"
+
+      - name: Send Slack notification if workflow failed
+        uses: someimportantcompany/github-actions-slack-message@0b470c14b39da4260ed9e3f9a4f1298a74ccdefd
+        if: ${{ failure() }}
+        with:
+          channel: ${{ secrets.DOCS_STAGING_DEPLOYMENT_FAILURES_SLACK_CHANNEL_ID }}
+          bot-token: ${{ secrets.SLACK_DOCS_BOT_TOKEN }}
+          color: failure
+          text: Staging undeployment failed for PR ${{ github.event.pull_request.html_url }} at commit ${{ github.head_sha }}. See https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}.