She is known for her appearances as a Mouseketeer on The New Mickey Mouse Club and her nine-year role as the preppy and wealthy Blair Warner on The Facts of Life.

At age 13, Whelchel was recruited in Texas by talent scouts who were looking for children interested in working with Disney Studios as a Mouseketeer on The New Mickey Mouse Club.

Having become a Christian when she was ten years old, Whelchel declined due to her religious beliefs, and the storyline was rewritten for the character of Natalie, portrayed by Mindy Cohn.

In 2021, Whelchel, Fields, and Cohn reunited again on the set of Live in Front of a Studio Audience's reenactment of the show's third season episode "Kids Can Be Cruel".

[5] Cohn has said that before his death, Norman Lear thought about a reboot of the series, however "one of the girls" went behind the others' backs and tried to work out a separate deal for a spinoff of her character.

I can speak that message in any situation, but a lot of churches — when they find out that I believe that there are many ways to experience God, not just Jesus, then the invitations kind of dry up.

"[8][9] Whelchel has written ten books on motherhood, child discipline, adult friendships, homeschooling, and finding Jesus through the development of holiday traditions.

[10] A former television star, she elected to keep her true identity a secret from the other contestants, many of whom were too young to have watched The Facts of Life during its original run and thus did not recognize her.

[11] On November 14, 2012, Whelchel announced via her Twitter account that she was suffering from West Nile fever and had been advised by her doctor that recovery would take approximately one year.

In the end, she received one jury vote from RC Saint-Amour and tied with returning contestant Michael Skupin for runner-up, both losing to eventual winner Denise Stapley.

[13] In April 2019, Whelchel hosted a The Facts of Life marathon on the MeTV television network,[14] as a lead-in for a preview of her series Collector's Call that debuted later that year and will be in Season 6 slated to begin in 2025.