[3] In 1926, Bradley moved to Los Angeles to conduct programs over KHJ Radio, an activity that led to his growing involvement in animation at the start of the talkie era.

He was a staff musician for Walt Disney (1929) and the Ub Iwerks studio (1930–1934), then became music director for Hugh Harman and Rudy Ising, who were hired to produce cartoon shorts for MGM.

Sight & Sound magazine quoted concertmaster Lou Raderman's mock complaint: "Scott writes the most blank-blank-blank difficult fiddle music in Hollywood … He is going to break my fingers!"

The first Bradley soundtrack album, Tom and Jerry & Tex Avery Too!, received a limited-edition release in 2006 and the "Cartoonia" suite was revived in a performance by the Cleveland Youth Orchestra in 2012.

The following year, "Tom and Jerry at MGM", a six-minute orchestral suite of Bradley cues reconstructed by Peter Morris and John Wilson, received its world premiere at a BBC Proms concert in London.