Born into a family of musicians (her mother is keyboard player Arlene Quatro, her aunt is singer Suzi Quatro and her grandfather Art Quatro was a jazz musician), of Italian and Hungarian descent on her mother's side and Irish and French descent on her father's side, Fenn traveled a lot with her mother and two older brothers before the family settled in Los Angeles when she was 17. She studied at the Lee Strasberg Theatre Institute. Despite a demure personality, she chose to start an acting career.

Sherilyn Fenn began her career with a number of B-movies including The Wild Life (1984, opposite Chris Penn), teen-fantasy movie The Wraith (1986) and erotic Two Moon Junction (1988, directed by 9½ Weeks' writer/producer Zalman King). She appeared in the 1985 cult teen-comedy Just One of the Guys in which she tries to seduce a teenage girl disguised as a boy Joyce Hyser.

Sherilyn FennFenn won her most outstanding role and made an indelible impression on the public when she was cast by David Lynch and Mark Frost as the sensual and reckless Audrey Horne, the high-school femme fatale from the critically acclaimed TV series Twin Peaks. The series ran from 1990 to 1991, and the character of Audrey was one of the most popular with fans, in particular for her unrequited love for FBI Special Agent Dale Cooper (played by Kyle MacLachlan), and a memorable scene in which she knotted a cherry stem in her mouth. "With Sherilyn Fenn, Twin Peaks came on and effortlessly destroyed every other show’s sexuality," said co-star James Marshall. In the show's second season, when the idea of pairing the characters was abandoned, Audrey was paired with other characters like Bobby Briggs (Dana Ashbrook) and John Justice Wheeler (Billy Zane). "Audrey’s been great for me. She has brought out a side of me that’s more mischievous and fun that I had suppressed, trying to be an adult. She has made it OK to use the power one has as a woman to be manipulative at times, to be precocious. She goes after what she wants vehemently and she takes it. I think that’s really admirable. I love that about her."

Shortly after shooting Twin Peaks' pilot episode, David Lynch gave her a small part in Wild at Heart, as a girl injured in a car wreck, opposite Nicolas Cage and Laura Dern, which won the Golden Palm Award at the 1990 Cannes Film Festival. "David’s direction was, ‘Only think of this: bobby pins, lipstick, wallet, comb, that’s it.’ It’s very abstract." "I just pictured her being able to do this," said Lynch of her scene, "she’s like a broken China doll."

After Twin Peaks, Fenn chose to focus on widening her range of roles and was determined to avoid typecasting. "They’ve offered me every variation on Audrey Horne, none of which were as good or as much fun." She turned down the Audrey Horne spin-off series that was offered to her, and unlike most of the cast, chose not to return for the 1992 prequel movie Twin Peaks: Fire Walk With Me, as she was then shooting Of Mice and Men.

After two nominations (Emmy and Golden Globe) and a pictorial in Playboy magazine, Fenn was propelled to stardom and became a major sex symbol. She turned to the independent world, to manage to carve out a career on her own terms as a character actress, and imposed her old Hollywood-style beauty with many varied roles. "I’m not consciously being the rebel. I don’t get considered for a lot of those big fat movies. The studios have their list of five actresses and whether they’re right or wrong for a role doesn’t matter. It’s how much money their last movie made. Not that I necessarily want to do them anyway. Because there’s very few that are big budget that have any substance or any depth or any integrity."

Fenn starred in the 1990 neo-noir black comedy Desire and Hell at Sunset Motel as a sultry, seductive femme fatale, opposite Whip Hubley and David Hewlett. She played John Dillinger's girlfriend Billie Frechette in ABC's 1991 gangster TV movie Dillinger opposite Mark Harmon, Will Patton and Patricia Arquette. Her acting coach Roy London chose her to star in his directorial debut Diary of a Hitman (nominated for the Critics Award at the 1991 Deauville Film Festival, and costarring Sharon Stone, also one of London’s alumni), in which she plays a mother determined to protect her child from hitman Forest Whitaker.

In 1992 she played a sad and lonely country wife, desperately in need to talk to somebody in Gary Sinise's film adaptation of Of Mice and Men (nominated for the Golden Palm at the 1992 Cannes Film Festival) opposite John Malkovich. "Sherilyn’s one of the reasons we got such a great ovation at Cannes," said Sinise. "Gary Sinise was one of the first people who didn’t see me like a lot of other people did," she said "It was a wonderful experience. Horton Foote adapted the novel and he fleshed out my character, and he made her much, much more." The same year saw her starring in John Mackenzie's Ruby as stripper Candy Cane DuJean, a character inspired by Marilyn Monroe, alongside Danny Aiello, Arliss Howard and Marc Lawrence. "I see these images of Marilyn," said Lawrence - who worked with Monroe - about Fenn, "she even moves like Marilyn." "She’s got a brain and all the right emotional instincts," said Mackenzie, "and that’s a great combination." In 1993 she starred in the romantic comedy Three of Hearts as Kelly Lynch and William Baldwin's love interest, and Carl Reiner's detective film parody Fatal Instinct as Armand Assante's devoted secretary and Sean Young and Kate Nelligan’s rival.

Her most notable film role to date was in the controversial Boxing Helena (nominated for the Grand Jury Prize at the 1993 Sundance Film Festival), directed by David Lynch's daughter Jennifer Chambers Lynch. Helena, in which she played a narcissistic seductress amputated and imprisoned by Julian Sands, was a way for Fenn to avoid being type-cast, with a radically different role from what she’d done in the past. Both Lynch and Fenn were proud of their work in it but the film - which was overshadowed by the lawsuits against Kim Basinger after she dropped out - ultimately was a critical and commercial failure. "Sherilyn is an amazing actress," said Lynch. "Jennifer’s one of the brightest person I know," said Fenn. "Boxing Helena was something that I think was pretty cool, but people judged it without even having seen it. It’s not perfect, but I think for the story that we were trying to tell, it turned out pretty good. What it signified was really powerful to me: how society puts us in boxes one way or another."

After a short break during which she married and gave birth to a son, Fenn portrayed Elizabeth Taylor in NBC's 1995 telemovie Liz: The Elizabeth Taylor Story. "Playing Elizabeth Taylor was probably the hardest job I’ve ever done." During the shooting, Fenn fought to keep integrity in the script, in order to accurately portray Taylor. "I just tried to play the truth of the woman. Not the legend, not the stories we hear about her." She also portrayed Potiphar's wife Zulaikha in Showtime's biblical TV movie Slave of Dreams opposite Adrian Pasdar and Edward James Olmos. The film was directed by multi-award winning Robert M. Young and produced by Martha and Dino De Laurentiis.

In the late 1990s, Fenn's career took a downturn, which she herself has attributed to her frankness ("When I go to an audition and I don't like the script, they know it.") and her lack of enthusiasm in traditional Hollywood films. "I was a brat", she admits. "I didn't like anything, even then. It was crazy, I was very picky. In other words, I didn't take advantage of what was happening necessarily then. But they also have a way of putting you in a category. I wasn't into playing the Hollywood game. I only responded to certain things."

Fenn then began to alternate TV movies and small independent films. In 1996 she joined the winning ensemble cast in the romantic comedy Lovelife as Jon Tenney's low self-esteemed girlfriend. The film was written and directed by Tru Calling's creator Jon Harmon Feldman and costarred Matt Letscher, Bruce Davison, Saffron Burrows and Carla Gugino. Fenn also starred in the 1997 romantic comedy Just Write as Hollywood tour bus driver Jeremy Piven's dream actress who mistakes him for a famous screenwriter.

She starred in the 1998 British psychological thriller Darkness Falls as Tim Dutton's unhappy wife, sequestered by despaired Ray Winstone. While shooting the film in the UK in 1997, Fenn hesitated to settle in London in order to start a European career and finally decided to stay in the USA.

Fenn's return to television was the lead role in Showtime's sitcom Rude Awakening (1998-2001) as Billie Frank, an alcoholic has-been ex-soap actress who tries to go sober and become a writer but continues to struggle with her self-destructive habits. "I liked the hard-core truth of Rude Awakening. But when I first read it, I was scared of it. Part of me was, like, it’s so unattractive! But I liked that it didn’t glamorize alcohol."

In 1999 Fenn reteamed with Chris Penn and Adrian Pasdar for Pasdar's directorial debut, the neo-noir Cement, in which she played a sultry, thoughtless femme fatale, the wife of jealous corrupt cop Chris Penn. The film, written by Farscape’s screenwriter Justin Monjo also starred Jeffrey Wright and Henry Czerny. She also reteamed with actor/director Bruce Davison for his 2001 award-winning family comedy, Showtime's Off Season alongside Rory Culkin, Hume Cronyn and Adam Arkin.

In 2002 Fenn was cast as Harleen Quinzel/Harley Quinn in WB's Birds of Prey but was replaced by Mia Sara before the series began (Fenn appeared in the unaired pilot episode but dropped out when the producers decided to reshoot the episode, due to scheduling conflicts). She played a criminal in the 2002 film, Swindle, opposite undercover cop Tom Sizemore. Fenn had small roles in the critically acclaimed The United States of Leland (2003) as a woman who represents happiness and joie de vivre to Ryan Gosling, and in Showtime's Cavedweller (2004) opposite Kyra Sedgwick. She co-starred in 2005 in the ultimately unreleased Lesser of Three Evils alongside Ho Sung Pak and Peter Greene.

In 2006 she will star in Whitepaddy alongside Lisa Bonet and Treasure Raiders with David Carradine. She will appear in the 2007 Dukes of Hazzard prequel, The Dukes of Hazzard: The Beginning.

Sherilyn Fenn guest-starred in numerous TV series like 21 Jump Street (1987) opposite her then-fiancé Johnny Depp and in a 1995 episode of HBO's Tales from the Crypt directed by Robert Zemeckis, alongside Isabella Rossellini and John Lithgow, in which she played the lover of Humphrey Bogart, who appeared in the episode via CGI special effects. In a 1997 episode of Friends she was Matthew Perry's wooden-legged girlfriend. She appeared in a 2001 episode of The Outer Limits in which her character was duplicated and played a manipulative woman in a 2002 episode of Law & Order: Special Victims Unit. She joined former co-stars Jeremy Piven on Cupid in 1998, and Mark Harmon on NCIS: Naval Criminal Investigative Service in 2004. In 2005 Fenn appeared on The 4400, in which she plays Jean DeLynn Baker, a 4400 who has the ability to grow toxin-emitting spores on her hands. Other appearances include Judging Amy in 2005 and CSI: Miami in 2006.

Fenn was one of several former Twin Peaks stars, such as Dana Ashbrook and Mädchen Amick, to have a recurring role on WB's Dawson's Creek. She also had a recurring role on Fox's Boston Public. She played two different roles on WB's Gilmore Girls, originally appearing in a season 3 episode, and reappearing as a different character, Anna Nardini, in the 6th season.

Fenn dated Prince and was engaged to Johnny Depp. She briefly dated Hollywood agent Jay Moloney. Fenn also dated photographer Barry Hollywood (who photographed her for the December 1990 issue of Playboy magazine). She married guitarist/songwriter Toulouse Holliday in 1994, and bore a son, Myles, in late 1993. The marriage came to an end in 1997.