One of Bell's first modeling jobs was an extended assignment in Japan. When she returned to California, she studied acting at the Beverly Hills Playhouse with Milton Katselas. Her first television acting role was one line on the sitcom Sugar and Spice (1990). Her first appearance in a film was as a body double for Isabella Rossellini in Death Becomes Her (1992). One of her first TV roles was on the HBO sitcom Dream On in 1994. Bell was featured in a nude scene opposite star Brian Benben.

From 1997 to 2005, Bell starred as U.S. Marine Corps Major Sarah MacKenzie on the hit television series JAG as a practicing attorney in the U.S. Navy's Judge Advocate General's Corps. Her earlier TV work also included an appearance featuring a nude love scene in a late night adult series called Hot line, which aired in the U.K. from 1994 to 1996, and is frequently re-run on the Showtime cable network in the U.S. Bell was featured in "The Brunch Club" episode.

In 2003, she had a supporting role as a television news anchor, Susan Ortega, in the comedy Bruce Almighty, starring Jim Carrey. She reprised the role with a cameo in the 2007 sequel Evan Almighty, starring Steve Carell. Bell appeared in the Sci Fi Channel miniseries The Triangle, presented in December 2005, playing an ocean engineer. In 2006, she was nominated in Saturn Award of Academy of Science Fiction, Fantasy & Horror Films for Best Supporting Actress on Television (The Triangle). In 2007, Bell starred in Lifetime's ensemble drama series Army Wives as Denise Sherwood, the wife of a US Army major, who is enduring domestic violence at the hands of her teenage son. Bell again will be playing main role in sequel Hallmark's The Good Witch ,The Good Witch's Garden, where also she is co-executive producing.

• The Good Witch's Garden (2009) (TV) (post-production) .... Cassandra Nightingale
  
• "Army Wives" .... Denise Sherwood (31 episodes, 2007-2009)
       - Incoming (2009) TV episode .... Denise Sherwood
       - Last Minute Changes (2008) TV episode .... Denise Sherwood
       - Departures, Arrivals (2008) TV episode .... Denise Sherwood
       - All in the Family (2008) TV episode .... Denise Sherwood
       - Thank You for Letting Me Share (2008) TV episode .... Denise Sherwood
        (26 more)
• The Good Witch (2008) (TV) .... Cassandra Nightingale
• Evan Almighty (2007) (uncredited) .... Susan Ortega - News Anchor
• Still Small Voices (2007) (TV) .... Michael Summer
• "Law & Order: Special Victims Unit" .... Naomi Cheales (1 episode, 2006)
  ... aka "Law & Order: SVU" (USA: promotional abbreviation)
  ... aka "Special Victims Unit" (New Zealand: English title)
       - Choreographed (2006) TV episode .... Naomi Cheales
• "Threshold" .... Daphne Larson (1 episode, 2006)
       - Outbreak (2006) TV episode .... Daphne Larson
• Company Town (2006) (TV) .... Maggie Shaunessy
• Sci Fi Inside: 'The Triangle' (2005) (TV) .... Emily Patterson
• "The Triangle" (2005) TV mini-series .... Emily Patterson
• "JAG" .... Lt. Col. Sarah 'Mac' MacKenzie / ... (194 episodes, 1996-2005)
  ... aka "JAG: Judge Advocate General" (Australia)
       - Fair Winds and Following Seas (2005) TV episode .... Lt. Col. Sarah 'Mac' MacKenzie
       - Dream Team (2005) TV episode .... Lt. Col. Sarah 'Mac' MacKenzie
       - Unknown Soldier (2005) TV episode .... Lt. Col. Sarah 'Mac' MacKenzie
       - Two Towns (2005) TV episode .... Lt. Col. Sarah 'Mac' MacKenzie
       - San Diego (2005) TV episode .... Lt. Col. Sarah 'Mac' MacKenzie
        (189 more)
• Babak & Friends: A First Norooz (2005) (V) .... Layla (English)
• "Waking the Dead" .... Sam James (1 episode, 2003)
       - Final Cut: Part 1 (2003) TV episode .... Sam James
• Bruce Almighty (2003) .... Susan Ortega