The 21-year-old has joined the Latics on a season-long loan from Elland Road.
The 21-year-old played 12 times in his first season at Elland Road last term after joining from Scottish side Motherwell, but only started two Championship games and failed to find the net.
After struggling to establish himself in the first team ahead of such competition as Chris Wood and Mirco Antenucci, Erwin signed a temporary deal to join League One side Oldham on Saturday.
The former Scotland youth international will be hoping to impress in the third tier and catch the eye of Whites manager Garry Monk from afar with a view to becoming a first-team star at Leeds in the future.
However, for now he is focused on his time at Boundary Park, and after explaining the way in which he likes to play in attack he also revealed that he has set himself a goal target, although he would not divulge just what that figure was.
Erwin told Oldham's website: "I found out about the interest from Oldham Athletic on Tuesday and then I completed the move soon after so I’m happy it’s finally done.
"I like to come short, run in behind and I can be a target man for the rest of the team. I’ve set myself a goals tally in my head but I won’t be telling you what that is.
"I just can’t wait to get out on the pitch and show the fans what I can do."
Erwin has already gained some League One experience from a loan spell at Bury last season, although he made just three appearances for the Shakers.