Uh, wha? Are you talking about the pilot? Because I’m pretty sure he wasn’t. He did win the trip with the nurse (Lt. Dish), but it was rigged for him to win so Dish wouldn’t actually have to go.
According to imdb it was the pilot. The actor was named George Morgan and when Mulcahy was asked to perform a priestly task he was making out with a nurse. William Christopher portrayed him from episode 3 onward. (Christopher spoke at a school I worked at on the subject of autism [he has an autistic son]- super nice guy who is, basically, Fr. Mulcahy in person.)