LOS ANGELES — Singer and pianist Frankie Randall, who was a Rat Pack favorite in the swinging ’60s and a staple of TV variety shows of that era, died Sunday at JFK Memorial Hospital in Indio. He was 76.

The cause was lung cancer, said his longtime companion, Melinda Read.

In addition to his TV appearances with Dean Martin and others, he recorded several songs, bringing his jazz-inflected, supper-club approach not only to such standards as “It Had to Be You,” but also to the TV theme from “Flipper” and the Who rock anthem “I Can See for Miles.”

He appeared at casino lounges and clubs across the country, including the Playboy Club in Los Angeles.

But Randall is most closely identified, not only in his professional but also in his personal life, with Frank Sinatra. The leader of the Rat Pack first heard Randall in a New York club and helped him get a recording contract. And although the “most memorable” gig of Randall’s career was his first appearance on the “Tonight Show,” he told the Palm Springs Desert Sun in 2011, the “best bill” he ever appeared on was with Sinatra and Sammy Davis Jr. in Atlantic City.

Later in life, Randall became the unofficial house pianist at Sinatra’s Rancho Mirage home. Living nearby, he would walk to Sinatra’s house when summoned to play piano for informal gatherings that could go late into the night, sometimes with Sinatra singing. “He called me his favorite piano accompanist,” Randall told the New York Daily News in 2007.

The two were so close that Sinatra, a few years before he died in 1998, gave Randall the musical arrangements to many of his songs.

For more than a year, Randall performed a Sinatra tribute show at a theater in Palm Springs.

He was born Frank Joseph Lisbona in Passaic, N.J., on Jan. 11, 1938. His father played the trumpet as a hobby, and Randall proved to be adept at playing the piano, picking up his first local paid performances at age 13.

His father insisted he get a college education in a non-music field in case he flopped as a performer. Randall earned a bachelor’s in psychology from Fairleigh Dickinson University in New Jersey but then pursued music in New York. Hearing him at Jilly’s, a club frequented by celebrities, Sinatra took him under his wing.

In 2007, Randall told the New York Daily News that he never saw Sinatra’s legendary temper. “The man I knew was the guy who would invite you to his home and cook you one of his favorite pasta dishes,” he said. “Those are wonderful memories.”

In addition to Read, Randall is survived by daughters Lisa Denicola of Verona, N.J., Laura Lisbona of San Francisco and Ava Lisbona of Los Angeles; son Frank Lisbona Jr. of Maplewood, N.J.; sister Grace Elaine Lisbona of New Jersey; and two grandchildren. His three marriages all ended in divorce.