Mac OS X Mail: How to Specify the Default Account

Mac OS X Mail makes it easy to send a message from a different email account.

But what if you use one of the "different" accounts more often than the account suggested by Mac OS X Mail as the default? Make the account you use most often to send messages the default!

Specify the Default Account in Mac OS X Mail

To specify a default email account in Mac OS X Mail:

Select Mail | Preferences... from the menu.

Go to the Composing category.
Select the desired account under Send new messages from: (or Send new mail from:) (under Addressing:).
- Select Account of selected mailbox to have OS X Mail choose the account based on the open folder; if you have your Gmail inbox open, for instance, if you start a new message, the Gmail address and account will be used as the default for sending.
Close the preferences window.

Specify the Default Account in Mac OS X Mail 1

To set the default account in Mac OS X Mail 1.x:

Select Mail | Preferences... from the menu.
Go to the Accounts tab.
Click on the account you want to make the default and
keep the mouse button pressed.
Drag the account to the top of the accounts list.
Release the mouse button.

Mac OS X Mail uses the topmost account in the account list as the default for outgoing messages. Of course, you can change the complete order of all accounts using this drag-and-drop method.

The individual account's folders under Inbox, for example, are also sorted in this order.

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