Lying in wait, Young shot him in the parking lot of the Marina Del Rey golf course and two months later, used the same gun to commit suicide.

The family later discovered an unopened letter having a cutout of Mr. Lennon, a picture of a gun pointed at his head, and the words "High Noon" (the time of the murder).

Lennon sang with David Crosby on his solo album Thousand Roads, and also performed vocals for the song "Suspension," which was the main title of the 1979 theatrical pilot of Buck Rogers in the 25th Century.

[citation needed] Lennon joined the classic yacht rock band Ambrosia on lead vocals in 2021 replacing Ken Stacey who exited in 2020.

Although Lennon did not appear in the 1987 Disney movie Double Switch, he did perform the vocals for the songs used in the soundtrack, "Turn up the Radio", "All Day, All Night", and "One Step Closer".

Lennon returned as Kompowsky to sing the extra verses Bart wrote for his sister in season 29's "Mr. Lisa's Opus".

In addition to The Simpsons, Lennon voiced Michael Jackstone on The Flintstone Kids' Just Say No Special, and various roles in The Story of Santa Claus, The Fall Guy, Eight Is Enough, and the TV series of Herbie the Love Bug.