LOS ANGELES – Frank Sinatra Jr., who carried on his famous father’s legacy with his own music career and whose kidnapping as a young man added a bizarre chapter to his father’s legendary life, died on Wednesday.

His real name was Francis Wayne Sinatra – his father’s full name was Francis Albert Sinatra – but he went professionally by Frank Sinatra Jr.Mr. Sinatra was the middle child of the elder Mr. Sinatra and Nancy Barbato Sinatra, who was the senior Mr. Sinatra’s first wife and the mother of all three of his children.

Mr. Sinatra’s older sister was Nancy Sinatra, who had a successful musical career of her own, and his younger sister was the TV producer Tina Sinatra.

Mr. Sinatra did sometimes get to see him from the wings of the stage, especially when his father performed for long stints in Las Vegas.

Mr. Sinatra followed his father into music as a teenager, eventually working for the senior Mr. Sinatra as his musical director and conductor.

The elder Mr. Sinatra died of a heart attack on May 14, 1998, at 82.Mr. Sinatra was able to provide a link to his father’s music after his death, performing his songs and arrangements on tours and especially in Las Vegas.

“Since my father’s death, a lot of people have made it clear that they’re not ready to give up the music,” Mr. Sinatra said in 2002.

Barry Keenan, a high school friend of Nancy Sinatra, was arrested with the other two suspects, Johnny Irwin and Joe Amsler, and convicted of conspiracy and kidnapping.

Mr. Sinatra had nearly two dozen TV and movie credits as an actor, most recently providing his voice for two episodes of “Family Guy.”.

Frank Sinatra Jr