Bell had her breakout performance as the title character in the television series Veronica Mars (2004–2007), a role she reprised in the 2014 spin-off film and the 2019 revival.

"[15] In 1992, Bell went to her first audition and won a dual role as a banana and a tree[16] in a suburban Detroit theater's production of Raggedy Ann and Andy.

[6] In 2001, Bell left New York University to play Becky Thatcher in the short-lived Broadway musical of The Adventures of Tom Sawyer.

She co-starred in the film The King and Queen of Moonlight Bay as Alison, a 17-year-old girl who travels to Arizona to reconnect with the father who abandoned her family.

[19] In 2004, Bell earned acclaim for her starring role in the Lifetime television film Gracie's Choice, which received one of the network's highest ratings.

[15] She made her debut in a theatrically released film with David Mamet's action thriller Spartan, as Laura Newton, the kidnapped daughter of the U.S. president, acting alongside Val Kilmer.

[20] Bell guest-starred on the HBO period drama series Deadwood, in a two-episode story arc ("Bullock Returns to the Camp" and "Suffer the Little Children").

Created by Rob Thomas, the series starred Bell as the seventeen-year-old anti-establishment high school student and private detective.

Frank Scheck of The Hollywood Reporter commented, "despite the starring presence of Kristen Bell, [the] young actress has far less interesting material to work with here than she does as [the character] 'Veronica Mars.

[27] A two-hour series finale aired in the United States on May 22, 2007, and on June 11, 2007, Thomas officially announced in an email to TV Guide's Michael Ausiello that Veronica Mars had been canceled by The CW.

[36][37] Shortly after the cancelation of Veronica Mars in early 2007, Bell filmed on location in Hawaii for a starring role as the title character in the Judd Apatow comedy Forgetting Sarah Marshall.

Bell lent her voice and likeness to the video game Assassin's Creed, which was released in November 2007 for consoles and April 2008 for the PC.

Director Kyle Newman received additional funding to shoot new scenes, but the busy schedules of the actors only allowed for filming in September 2007.

[43][44] Bell co-starred alongside singers Christina Aguilera and Cher in the backstage musical film Burlesque, which was released in November 2010.

[48] Bell starred as Jeannie van der Hooven, the female lead on the Showtime comedy series House of Lies, which premiered on January 8, 2012.

Bell and series creator Rob Thomas launched a fundraising campaign to produce the film through Kickstarter and attained the $2 million goal in less than ten hours.

[53][54] In September 2014, Bell starred with her husband, Dax Shepard, in a commercial for the Samsung Galaxy Tab S.[55] It was so popular (with over 20 million YouTube views) that they did another for the holiday season.

In November 2017, she played a housewife (with Dax Shepard as her husband) preparing for a Christmas party in Sia's music video for "Santa's Coming for Us".

[61] In 2018, she began hosting the web series Momsplaining with Kristen Bell, with episodes airing on the Ellen DeGeneres video platform Ellentube.

[66] In 2019, she again reprised her role of Princess Anna in the video game Kingdom Hearts III[67] and the sequel Frozen II[68] which was released on November 22, 2019.

[76] In 2021, Bell produces and voices a lead character in the Amazon Prime Video animated musical pre-school series Do, Re, & Mi.

[78] Bell starred alongside Kirby Howell-Baptiste as a pair of housewives who created a multi-million dollar coupon scam in the comedy film Queenpins.

"[18] Vanessa Juarez of Entertainment Weekly commented that Bell's roles on Veronica Mars, Heroes and as a Star Wars fanatic in Fanboys have "solidif[ied] her placement at the center of the geek universe," while Rodney Rothman stated, "I guess she's cornered the market on losers.

"[93] Bell's work is often compared to Sarah Michelle Gellar's portrayal of the title character on the television series Buffy the Vampire Slayer.

[94] Frank Scheck of The Hollywood Reporter stated that Bell was "arguably the television successor [to Gellar's portrayal of Buffy] when it comes to fighting bad guys."

After section 3 of the Defense of Marriage Act was ruled unconstitutional by the Supreme Court on June 26, 2013, Bell asked Shepard to marry her through Twitter,[105] which he accepted.

Because Instagram and magazines and TV shows, they strive for a certain aesthetic, and everything looks so beautiful, and people seem like they don’t have any problems, but everyone’s human.

Everyone feels yucky on the inside sometimes.” [112] In an interview with Jimmy Kimmel in August 2018, Bell discussed why she wears scuba gloves while swimming.

The goal of the organization is to create awareness of the plight of Northern Ugandans who are caught in the midst of a civil war between the government and Joseph Kony's Lord's Resistance Army.

[131] In 2019, Bell and her husband founded the company Hello Bello that markets plant-based baby care products said to be environmentally friendly and affordable.