Ernie is the owner of the juice bar at Angel Grove Gym and Juice Bar in Angel Grove. The Angel Grove Youth Center, where the juice bar is located, is the most popular hangout spot for teens in the area.
Though the Juice Bar appears in Issue 1, Ernie does not. It is not until MMPR/TMNT II Issue 1 that Ernie is seen at the counter taking a drink order from Zack Taylor. Donatello and Michelangelo arrive, both cloaked by holograms to make them appear human. They start to place an order, but Don’s cloaking device begins to glitch and Billy Cranston rushes him away before Ernie notices.
Near the end of MMPR/TMNT II issue 5, when all of the cloaked Turtles join the Power Rangers at the Juice Bar, Ernie gathers them together in order to take a group picture.