Bell is the daughter of a Scottish father and Iranian mother. Her parents divorced, and then she and her mother moved to Los Angeles, California, when she was three years old. She became a naturalized citizen of the United States at the age of 12. She acted in various television advertisements as a child. She attended the University of California, Los Angeles (UCLA) with an interest in becoming either a biomedical engineer or a physician but dropped out to become a full-time model. One of her 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).

On September 14, 2006, Reuters/Hollywood Reporter announced that Catherine Bell had joined the cast of Lifetime's ensemble drama pilot "Army Wives". In the projected series, Sally Pressman stars as a sassy woman from the wrong side of the tracks who marries a soldier, moves her kids to a military base and becomes friends with a diverse group of Army wives, three of them played by Catherine Bell, Kim Delaney, and Brigid Brannagh. Bell will play the wife of a US Army major, a devoted homemaker who is enduring physical abuse at the hands of her teenage son. In December, Lifetime announced it would produce 13 episodes of the series for 2007. Bell's character is named Denise Sherwood.

Bell has also acted in the Sci-Fi Channel miniseries, The Triangle, presented in December 2005, where she played the role of an ocean engineer.

• October 27, 2008: Hottie Clip #329: Catherine Bell In A Sexy Bra & Panties - ARMY WIVES
• August 15, 2008: Bell Turns 40!: That's right gents, our favourite "JAG" babe has officially turned the tender age of 40 and has been inducted into the "Hottie Hall of Fame" for her age group amongst acresses such as Diane Lane and Halle Berry. This sugar pie has had us on...
• February 4, 2008: Superbowl Hotties #1: As everybody knows at this point the great Giants took the big yesterday and ended the loosing streak of New England in a sweet victory. It was an awesome game but it did slow down quite a bit by the end. Even though the game may have been a...
• November 22, 2007: Bell's A Hot Witch: Just picture it gents...Catherine Bell as a smokin' hot witch and she moves into your town to wreak havoc and show off her amazing cleavage. Does that not sound like the hottest thing ever? It's certainly close for me and starting in early 2008,...
• August 8, 2007: Is Bell Next Bellucci?: You all might think I'm absolutely nuts about this but I have to be perfectly honest, I think that Catherine Bell could possibly be our next Monica Bellucci. With her perfect curves, sensual smile and sparkling eyes, I think she's the most...