diff --git a/tools/find-inactive-collaborators.mjs b/tools/find-inactive-collaborators.mjs
index 2951d81c534696..c205e931bd87b0 100755
--- a/tools/find-inactive-collaborators.mjs
+++ b/tools/find-inactive-collaborators.mjs
@@ -22,27 +22,33 @@ async function runGitCommand(cmd, mapFn) {
   const errorHandler = new Promise(
     (_, reject) => childProcess.on('error', reject)
   );
-  const returnedSet = new Set();
+  let returnValue = mapFn ? new Set() : '';
   await Promise.race([errorHandler, Promise.resolve()]);
+  // If no mapFn, return the value. If there is a mapFn, use it to make a Set to
+  // return.
   for await (const line of lines) {
     await Promise.race([errorHandler, Promise.resolve()]);
-    const val = mapFn(line);
-    if (val) {
-      returnedSet.add(val);
+    if (mapFn) {
+      const val = mapFn(line);
+      if (val) {
+        returnValue.add(val);
+      }
+    } else {
+      returnValue += line;
     }
   }
-  return Promise.race([errorHandler, Promise.resolve(returnedSet)]);
+  return Promise.race([errorHandler, Promise.resolve(returnValue)]);
 }
 
 // Get all commit authors during the time period.
 const authors = await runGitCommand(
-  `git shortlog -n -s --max-count="${SINCE}" HEAD`,
+  `git shortlog -n -s --email --max-count="${SINCE}" HEAD`,
   (line) => line.trim().split('\t', 2)[1]
 );
 
 // Get all commit landers during the time period.
 const landers = await runGitCommand(
-  `git shortlog -n -s -c --max-count="${SINCE}" HEAD`,
+  `git shortlog -n -s -c --email --max-count="${SINCE}" HEAD`,
   (line) => line.trim().split('\t', 2)[1]
 );
 
@@ -52,7 +58,7 @@ const approvingReviewers = await runGitCommand(
   (line) => /^    Reviewed-By: ([^<]+)/.exec(line)[1].trim()
 );
 
-async function retrieveCollaboratorsFromReadme() {
+async function getCollaboratorsFromReadme() {
   const readmeText = readline.createInterface({
     input: fs.createReadStream(new URL('../README.md', import.meta.url)),
     crlfDelay: Infinity,
@@ -69,14 +75,22 @@ async function retrieveCollaboratorsFromReadme() {
       break;
     }
     if (line.startsWith('**') && isCollaborator) {
-      returnedArray.push(line.split('**', 2)[1].trim());
+      const [, name, email] = /^\*\*([^*]+)\*\* &lt;(.+)&gt;/.exec(line);
+      const mailmap = await runGitCommand(
+        `git check-mailmap '${name} <${email}>'`
+      );
+      returnedArray.push({
+        name,
+        email,
+        mailmap,
+      });
     }
   }
   return returnedArray;
 }
 
 // Get list of current collaborators from README.md.
-const collaborators = await retrieveCollaboratorsFromReadme();
+const collaborators = await getCollaboratorsFromReadme();
 
 console.log(`In the last ${SINCE} commits:\n`);
 console.log(`* ${authors.size.toLocaleString()} authors have made commits.`);
@@ -85,10 +99,10 @@ console.log(`* ${approvingReviewers.size.toLocaleString()} reviewers have approv
 console.log(`* ${collaborators.length.toLocaleString()} collaborators currently in the project.`);
 
 const inactive = collaborators.filter((collaborator) =>
-  !authors.has(collaborator) &&
-  !landers.has(collaborator) &&
-  !approvingReviewers.has(collaborator)
-);
+  !authors.has(collaborator.mailmap) &&
+  !landers.has(collaborator.mailmap) &&
+  !approvingReviewers.has(collaborator.name)
+).map((collaborator) => collaborator.name);
 
 if (inactive.length) {
   console.log('\nInactive collaborators:\n');