After auditioning and appearing in a local production of The King and I at the age of 8, she sent her school picture to a San Francisco Talent Agency and landed a series of TV commercials.

In 1984, Whelan graduated from the Buckley School in Sherman Oaks, California[5] with a stint at Guildford College in Surrey, England where she studied English Literature[2] before coming back to Los Angeles.

[6] In the mid-1980s, in Los Angeles, having returned from England and with The Love Boat coming to an end, Whelan moved to New York City and worked as an event producer at Madison Square Garden,[7] where she helped set up acts.

Whelan competed against other celebrity 1970s TV stars, including Mackenzie Phillips, Nell Carter, Cindy Williams, Joan Van Ark, Erin Moran, Erik Estrada, and Fred "Re-run" Berry.

In October 2008, she made her New York City cabaret debut with her one-woman show Jill Whelan: An Evening in Dry Dock at the Metropolitan Room.

[8] From September to November 2011, Whelan appeared in the British farce Move Over Mrs. Markham at Stage West Theatre Restaurant in the Toronto, Ontario area.

[10] Whelan met her first husband, Brad St. John, as an associate producer for KCOP-TV in Los Angeles, shortly after leaving Madison Square Garden.