By Oliver Gettell
Updated October 19, 2016 at 12:00 PM EDT
Credit: ABC Photo Archives/ABC via Getty Images

Eddie Applegate, the actor known for playing the easygoing high school boyfriend of Patty Lane on The Patty Duke Show, died Monday in Los Angeles at age 81. His son Michael confirmed his death to the New York Times.

Applegate portrayed Richard Harrison on 88 episodes of the 1960s sitcom, which starred Duke as identical cousins Patty (an all-American girl) and Cathy (a prim Scottish teen). Duke died earlier this year, in March, and William Schallert, who played her father on the show, died in May.

A native of Wyncote, Pennsylvania, Applegate moved to New York City after high school and appeared in commercials and on TV shows. He was cast on Patty Duke after producers saw him in a touring production of Bye Bye Birdie.

His other screen credits include the television series The Many Loves of Dobie Gillis, The Lucy Show, and Gunsmoke, and the films Easy A and A Ticklish Affair. Applegate reunited with his Patty Duke costars on the 1999 TV movie The Patty Duke Show: Still Rockin’ in Brooklyn Heights.

Applegate’s survivors include three children, a sister, and six grandchildren.