Mack at It Again is a 1914 short comedy film starring Mabel Normand and Mack Sennett.
 Mack Sennett also directed the film.
 The picture was produced by Sennett's Keystone Film Company and distributed by Mutual Film.
Warner LeRoy (March 3, 1935 – February 22, 2001), was a New York businessman.
 LeRoy was the son of film producer-director Mervyn LeRoy and Mervyn's second wife, Doris Warner, and was the grandson of Harry Warner, one of the founders of Warner Bros. and a major contributor to the development of the film industry.
W-L Ranch Co. was an American Thoroughbred horse racing and breeding partnership between Hollywood film studio executive Harry M. Warner and film director Mervyn LeRoy.
 Warner's daughter, Doris, was married to Mervyn LeRoy.
Mervyn LeRoy (October 15, 1900 – September 13, 1987) was an American film director, film producer and occasional actor.
Girl Crazy was a 1929 comedy film directed by Mack Sennett and starring Andy Clyde as "a girl-crazy sexagenarian".
 The film's story is credited to Hampton Del Ruth, Alfred J. Goulding, Harry McCoy, Earle Rodney, and Mack Sennett.
Mack Sennett (born Michael Sinnott; January 17, 1880 – November 5, 1960) was a Canadian-born American director and actor and was known as an innovator of slapstick comedy in film.
 During his lifetime he was known at times as the "King of Comedy".
 His short "Wrestling Swordfish" was awarded the Academy Award for Best Live Action Short Film in 1932 and he earned an Academy Honorary Award in 1937.
Sing, Bing, Sing is a 1932 Mack Sennett Star Comedy (No.
 S3627) starring Bing Crosby and directed by Babe Stafford.
 This was the fifth of the six short films Crosby made for Mack Sennett and which helped launch his career as a solo performer.
At Coney Island, also known as Cohen at Coney Island, is a 1912 American short silent comedy starring Mack Sennett, Mabel Normand, and Ford Sterling.
 Sennett also directed and produced the film.
 According to the book "Mack Sennett's Fun Factory: A History and Filmography of His Studio and His Keystone and Mack Sennett Comedies, with Biographies of Players and Personnel", Sennett claimed this was the first Keystone Studios production, shot on location at Coney Island on July 4, 1912.
 It was the eleventh Keystone film released, on a split-reel with "A Grocery Clerk's Romance".
Blue of the Night is a 1932 Mack Sennett Star Comedy (No.
 S3628) starring Bing Crosby and directed by Leslie Pearce.
 This was the last of the six short films Crosby made for Mack Sennett and which helped launch his career as a solo performer.
Mabel's Awful Mistakes is a 1913 film starring Mabel Normand and directed by Mack Sennett.
 The film also features Mack Sennett, Ford Sterling and Edgar Kennedy.

Question: Who held more roles in the film industry, Mervyn LeRoy or Mack Sennett?
Answer: Mervyn LeRoy