StrengthsFinders defines being an Achiever this way:
People who are especially talented in the Achiever theme have a great deal of stamina and work hard. They take great satisfaction from being busy and productive.
I think that pretty much covers it. Almost everyone you find in a leadership role will have this trait in their top five. Those that don’t have to find other ways to propel the team they lead other than by showing them what that kind of satisfaction looks like personally.