While Combs was learning to walk, she fell and hit her head on a marble table, resulting in a noticeable 'split' at the top of her right eyebrow.

[9] When she was 14 years old, Combs landed her first major role in Sweet Hearts Dance (1988), a comedy drama film directed by Robert Greenwald.

[10] Her next major role was in Oliver Stone's Born on the Fourth of July (1989), a film adaptation of the best selling autobiography of the same name by Vietnam War veteran Ron Kovic.

[10] Her other roles included Helena in the 1989 anthology film New York Stories, and Kim Fields in Hal Hartley's Simple Men (1992).

[10] In 1998, Combs landed a lead role in The WB television series Charmed, in which she portrayed Piper Halliwell, the middle of three sisters who are witches.

During Charmed, Combs made an uncredited cameo appearance in Steven Soderbergh's Ocean's Eleven (2001), and starred opposite Charisma Carpenter in the romantic comedy film See Jane Date (2003), portraying the role of "a struggling actress whose career benefits from an affair with an A-list actor.

"[10] In 2007, she starred in the Lifetime television film Point of Entry (also titled Panic Button) as Kathy Alden, a wife and mother of a single child whose family moves to a "beautiful and supposedly secure gated community after she's the victim of a violent house break-in.

[19][20] Combs and Doherty starred in their own road trip reality show Off the Map with Shannen & Holly, which premiered on Great American Country on January 2, 2015.

[21][22] The six-episode series followed the pair traveling across southeastern United States, with stops in Kentucky, Tennessee, Mississippi, Alabama, Georgia and Florida.

[23] In January 2016, Combs starred in the Hallmark Channel television film Love's Complicated, playing the lead role of Leah Townsend, a big city novel writer and senator's daughter who is "known for being a people pleaser.