Answer by taking a quote from the following article:

Robert Charles Benchley (September 15, 1889 - November 21, 1945) was an American humorist best known for his work as a newspaper columnist and film actor. From his beginnings at The Harvard Lampoon while attending Harvard University, through his many years writing essays and articles for Vanity Fair and The New Yorker and his acclaimed short films, Benchley's style of humor brought him respect and success during his life, from his peers at the Algonquin Round Table in New York City to contemporaries in the burgeoning film industry. Benchley is best remembered for his contributions to The New Yorker, where his essays, whether topical or absurdist, influenced many modern humorists. He also made a name for himself in Hollywood, when his short film How to Sleep was a popular success and won Best Short Subject at the 1935 Academy Awards, and through his many memorable appearances in films such as Alfred Hitchcock's Foreign Correspondent (1940) and Nice Girl?

Benchley had continued to receive positive responses from his performing, and in 1925 he accepted a standing invitation from film producer Jesse L. Lasky for a six-week term writing screenplays at $500. While the session did not yield significant results, Benchley did get writing credit for producing the title cards on the Raymond Griffith silent film You'd Be Surprised (released September 1926), and was invited to do some titling for two other films.  Benchley was also hired to help with the book for a Broadway musical, Smarty, starring Fred Astaire. This experience was not as positive, and most of Benchley's contributions were excised and the final product, Funny Face, did not have Benchley's name attached. Worn down, Benchley moved to his next commitment, an attempt at a talkie version of "The Treasurer's Report". The filming went by quickly, and though he was convinced he was not good, The Treasurer's Report was a financial and critical success upon its release in 1928. Benchley participated in two more films that year: a second talking film he wrote, The Sex Life of the Polyp, and a third starring but not written by him, The Spellbinder, all made in the Fox Movietone sound-on-film system and released by Fox Films. The films enjoyed similar success and were critically acclaimed, and Benchley was signed to a deal to produce more films before heading back to New York to continue writing. As Life would say following his eventual resignation in 1929, "Mr. Benchley has left Dramatic Criticism for the Talking Movies".  During the time that Benchley was filming various short films, he also began working at The New Yorker, which had started in February 1925 under the control of Benchley's friend Harold Ross. While Benchley, along with many of his Algonquin acquaintances, was wary of getting involved with another publication for various reasons, he completed some freelance work for The New Yorker over the first few years, and was later invited to be newspaper critic. Benchley initially wrote the column under the pseudonym Guy Fawkes (the lead conspirator in the English Gunpowder Plot), and the column was well received. Benchley tackled issues ranging from careless reporting to European fascism, and the publication flourished. He was invited to be theatre critic for The New Yorker in 1929, leaving Life, and contributions from Woollcott and Parker became regular features in the magazine. The New Yorker published an average of forty-eight Benchley columns per year during the early 1930s.  With the emergence of The New Yorker, Benchley was able to stay away from Hollywood work for a number of years. In 1931, he was persuaded to do voice work for RKO Radio Pictures for a film that would eventually be titled Sky Devils, and he acted in his first feature film, The Sport Parade (1932) with Joel McCrea. The work on The Sport Parade caused Benchley to miss the fall theatre openings, which embarrassed him (even if the relative success of The Sport Parade was often credited to Benchley's role), but the lure of filmmaking did not disappear, since RKO offered him a writing and acting contract for the following year for more money than he was making writing for The New Yorker.

what did he do in hollywood?
Benchley was filming various short films,