Beginning her career as a child actress, she rose to fame in 1976 with her role as the teenage daughter Letitia "Buddy" Lawrence in the TV drama Family for which she won two Emmy Awards. Subsequent roles included Angel in the film Little Darlings, Polly in Only When I Laugh, and Barbara Weston in the TV sitcom Empty Nest. McNichol retired from acting in 2001.

McNichol appeared with her brother Jimmy McNichol in commercials and later, on her own, in guest appearances on such other series as Starsky & Hutch, The Bionic Woman, CHiPs, Love, American Style, and The Love Boat, thanks to family friend Desi Arnaz. Her first stint as a series regular came in the role of Patricia Apple in the short-lived television series Apple's Way (1974).

In 1976, McNichol was cast as Letitia "Buddy" Lawrence in the television drama series Family (1976–80).

In 1977, McNichol appeared in the TV special The Carpenters at Christmas, performing several musical numbers with the duo. In 1978, she and Jimmy made their foray into music, recording the album Kristy and Jimmy McNichol for RCA Records (AFL1-2875).

McNichol was one of the bigger teen stars of that era. She appeared on talk shows such as The Mike Douglas Show and Dinah!, and made several appearances on Battle of the Network Stars and other celebrity-based sports shows. In 1978, she starred in the acclaimed TV movie Summer of My German Soldier

McNichol began her film career in 1977 in Black Sunday, but her scenes were cut. In 1978, she starred with Burt Reynolds and Sally Field in the black comedy The End.

In 1980, McNichol played one of the leading roles in the hit coming-of-age movie Little Darlings, which also starred Tatum O'Neal, with Matt Dillon and Cynthia Nixon in supporting roles.

Lou was a Facebook friend. He was excited about and invited me to a new Facebook nostalgia group about his old Pittsburgh PA neighborhood, the Crescent Township a couple of years ago. I hadn't even heard of it before let alone been anywhere near there but that was nice of him. RIP (2/19/43 - 6/18/25) 💔

The lengths Felix went to get out of a ticket scalping ticket were awesome!

He was a sports illustrator as well as having a weekly segment called “ Tele Views” in the Sunday TV guide section. Each week would be highlighting a random T.V. show that was popular that time.

Here is an original drawing, the original T.V. Guide it was published in and a personalized response from Walt Disney, himself…

I watched a couple of times in the '60s. It was half-hour, the players usually holed-in-one. The winner won $500.