After attending Santa Ana High School, Musick played college football at the University of Southern California (USC) from 1929 to 1931.

It was at USC he earned the nickname "Sweet" Musick as he helped lead the Trojans to two Rose Bowl victories and a national championship in 1931.

[1] While still a professional football player, Jim Musick began working in the offseason as a deputy for the Orange County Sheriff's Department, which was headquartered in his hometown of Santa Ana, California.

After retirement from the NFL, Musick took up law enforcement full-time, except for a period during World War II when he served as a US Marine officer.

[3] In 1946, Musick won election to the first of seven consecutive terms as Orange County Sheriff, remaining at the post until deciding not to seek re-election in 1974.