Using a domain user account for SQL Agent works fine in SQL 2012 (and SQL 2005, 2008, 2008R2, 2014), you just have to give it the correct rights.
It needs:
Act as part of the operating system
Adjust memory quotas for a process
Bypass traverse checking
Log on as a batch job
Log on as a service
Replace a process level token
It does not need to be a member of the windows Administrator group unless you enable the 'Automatically start SQL Server / SQL Agent if it fails'.
The Agent account will also need to be a Sysadmin account in SQL Server.
Original author: https://github.com/SQL-FineBuild/Common/wiki/ 1-click install and best practice configuration of SQL Server 2019, 2017 2016, 2014, 2012, 2008 R2, 2008 and 2005.
When I give food to the poor they call me a saint. When I ask why they are poor they call me a communist - Archbishop Hélder Câmara