She is the daughter of Andrew and Karin Wührer, and has three siblings. As a teenager she sang in nightclubs, sneaking out of the family home to perform. Kari began studying acting at the age of 13. She studied drama at New York University, Columbia University, and the Royal Academy of Dramatic Arts in London with famed teacher Uta Hagen.

Her first television break was working for MTV as a VJ and as a co-host in Remote Control (1987). She then starred in over a dozen straight-to-video sexploitation movies, most notably Sex and the Other Man (1996), Vivid (1997) (also released as Luscious), and Spider's Web (2001).

She came to mainstream fame in 1997 on the series Sliders as Maggie Beckett, joining the cast as a regular and staying until the show ended in 2000.

Later mainstream movie roles include:

Anaconda (1997) Berserker (2001) Eight Legged Freaks (2002) Wührer is also well known by many gamers for her role in Westwood Studios' PC game Command & Conquer: Red Alert 2 and it's subsequent expansion pack, Yuri's Revenge as Agent Tanya Adams.

Wuhrer signed a record deal with Rick Rubin and her debut album was called Shiny, released in 1999. She plays the guitar and the flute as well as sings.

Wührer, who considered an offer to appear nude in Playboy in 1998, was later voted #73 in the FHM 100 Sexiest Women in the World 2001, #36 in Maxim magazine's 50 sexiest women countdown (1999), #64 on Celebrity Skin's 100 Sexiest Stars of All Time, and #4 in the Celebrity Nudity Database most popular actresses (1999).

Her breast implants ruptured during the filming of Eight Legged Freaks so she had them removed. She later wrote an article for a women's magazine about the insecurities that led her to get implants early in her career and the sense of self-acceptance she acquired.

In the late 1980s she dated rock singer Dean Davidson. She was married to Daniel Salin in 1995, and divorced in 1999. In the summer of 2000, during an appearance on a cable network show, she publicly stated that her boyfriend Henry Rollins dumped her via email. Kari is presently married to the film producer James Scura since 2003. She and her husband have two children, a boy named Enzo, born January 2004, and a girl named Evangeline, born April 2006.

From February 3, 2005 through November 2005 Wuhrer joined the cast of the soap opera General Hospital as FBI Agent Reese Marshall, the former love interest of mobster Sonny Corinthos (Maurice Benard). Wuhrer's character died after suffering some minor injuries in a train wreck. In January 2006, Wuhrer announced that she was suing General Hospital, claiming that she was fired because of her pregnancy. Wuhrer plans to support her claim using testimony from another former actress on General Hospital, Lesli Kay, who claims she was fired for the same reason.