Benchley served in the United States Navy and was assigned to the Naval Security Group during the Vietnam War.

He later worked for a public television station in Washington, D.C. During the early-1970s, he wrote and acted in an anti-shoplifting film for the Florida Attorney General's office titled "High Pockets At Full Noon".

That same year, he and co-actor Bill Grimmette were nominated for a Helen Hayes Award for their performances in Athol Fugard's show "The Blood Knot".

During the 1990s, Benchley revived two Peter Cook and Dudley Moore stage productions, Beyond the Fringe and Good Evening in the Washington, D.C., area.

In 2009, he and co-editor Kevin C. Fitzpatrick published "The Lost Algonquin Round Table", a collection of early writings by his grandfather Robert Benchley and other members of the fabled New York literary gang.