Participate and complete a game on an EA SPORTS™ Hockey League team while you're wearing a custom jersey.
If you're creating a new team you have the option of selecting existing or custom jerseys and their colour scheme. For the purpose of this achievement and to look super bad ass, you should select custom.
EA SPORTS™ Hockey League games require at least two people to play against another team so have someone else ready to play on your team with you. Complete the match and it should pop post-game.