Reynolds was born on April 4, 1923, to Frank Eugene Blumenthal, a businessman and entrepreneur, and Maude Evelyn (Schwab) Blumenthal, a model, in Cleveland, Ohio. Reynolds initially was raised in Detroit, before the family relocated to Los Angeles in 1934.

Reynolds made his screen debut in the 1934 Our Gang short Washee Ironee, and for the next three decades made numerous appearances in films such as Captains Courageous (1937), Love Finds Andy Hardy (1938), Boys Town (1938), They Shall Have Music (1939), Santa Fe Trail (1940), Adventure in Washington (1941), Eagle Squadron (1942) and The Country Girl (1954) and on television series like I Love Lucy, Armstrong Circle Theatre, Whirlybirds, and Hallmark Hall of Fame. He was contracted to MGM between 1937 and 1940.

In 1957, Reynolds joined forces with Frank Gruber and James Brooks to create Tales of Wells Fargo for NBC. During the program’s five-year run he wrote and directed numerous episodes.

Reynolds was married to actress-turned-author Bonnie Jones, who appeared in five episodes of M*A*S*H as Lt. Barbara Bannerman, from 1972 until 1975, when the couple divorced. He and his second wife, actress Ann Sweeny, who also appeared on M*A*S*H as Nurse Carrie Donovan in the episode “Hanky Panky”, married in 1979 and have one son, Andrew Reynolds.

Reynolds was elected President of the Directors Guild of America in 1993, a position he held until 1997.

Reynolds died at the age of 96 of heart failure on February 3, 2020, at Providence St. Joseph Medical Center in Burbank, California.