Later he joined RKO Pictures in 1935,[2] where he worked on the film adaptation of Leslie Charteris' The Saint in New York.

Actor Lon Chaney, Sr. tells of confronting Universal studio manager William Sistrom in 1918 demanding a payrise and contract.

During World War II, the Sistroms opened their Hollywood home to many American servicemen.

Boulter's daughter Carol Haynes Johnson, who was 8 when they married, described William as "gentle, loving, giving.

"[5] After the wedding, William retired, and the family moved to Phoenix, Arizona, where he managed a turkey ranch in Buckeye, about 40 mi (64 km) outside the city.