How to Set a Default Signature for an Account in Mac OS X Mail

Sailor Professional Gear
You do not need this to add a signature in OS X Mail. Flickr/semihundido

Have OS X Mail insert a specific signature automatically depending on the email account.

Signing off for Different Email Roles and Accounts

I use the same signature for all my emails, but this is only because I can barely think of one signature that is only mildly silly. Normally, using different signatures for work (boringly useful) and private (annoyingly funny) accounts, for example, makes perfect sense.

It makes sense, and Apple's Mac OS X Mail can put the correct signature for an account in your emails automatically. But first, you have to specify which signature you want to be the default for each account, and which you want to be able to select manually when composing an email.

Set a Default Signature for an Account in Mac OS X Mail

To define the default signature for an email account in Mac OS X Mail:

  1. Select Mail | Preferences... from the menu.
    • ​You can also press Command-, (comma).
  2. Go to the Signatures tab.
  3. Highlight the desired account.
  4. Select the desired signature under Choose Signature:.
    • To create a new signature for an account:
      1. Press the + button.
      2. Type a name that will help you recognize the signature.
        • ​Typical names would include "Work", "Personal", "Gmail" or "Montaigne quote", of course.
      3. Press Enter.
      4. Edit the signature's text in the area to the right.
        • ​Though you will not see a formatting toolbar, you can apply text styles to your signature's content.
          Use Format | Show Fonts in the menu, for instance, to set text styles, or drag and drop images to where you desire them in the signature. You can also insert links and apply more formatting easily if you compose the signature's text in a new email and copy it to the Signatures preferences window.
        • Alternatively, check Always match my default message font.
          This will have OS X Mail set the entire signature's text using the default message text font, and your signature will not only blend in well with your emails, but OS X Mail will also be able to send small and efficient text-only email messages (when you apply no formatting to any text while composing the email).
        • Add the standard signature delimiter to your signature. OS X Mail will not do so automatically.
        • Keep the signature to 5 lines of text.
    • To use a signature created for another account (or for no account in particular):
      1. Select All Signatures in the accounts list (or, of course, the account for which you created the signature).
      2. Drag the signature you want to use to the desired account.
  1. ​Close the Signatures preferences window.

Override the Default Signature for a Message

To use a signature different from the default for a message you are composing in OS X Mail:

  1. ​Select the desired signature under Signature: in the email's header area (below the Subject:).
    • ​OS X Mail will replace the default signature, if any, with your selection.
    • If you have edited the signature, OS X Mail will instead append the newly selected one.
    • If you do not see the signature you want to use in the list:
      1. ​Select Edit Signatures instead.
      2. Go to All Signatures.
      3. Drag and drop the desired signature to the account you are using to compose the email.
      4. Close the Signatures preferences window.
      5. Close the email composition window.
      6. Click Save to save the message as a draft.
      7. Open the Drafts folder.
      8. Double-click the message you just saved.

    (Updated March 2016, tested with OS X Mail 9)