She has appeared in various television series, including Boston Legal (2004–2006), Surface (2005–2006), How to Make It in America (2010–2011), Childrens Hospital (2008–2016), and Bless This Mess (2019–2020) and in films including Over Her Dead Body (2008), What Happens in Vegas (2008), It's Complicated (2009), No Strings Attached (2011), Million Dollar Arm (2014), No Escape (2015), Man Up (2015), The Secret Life of Pets (2016), Shot Caller (2017), Home Again (2017), The Secret Life of Pets 2 (2019), and Black Panther: Wakanda Forever (2022).

[13][14] At Rose Bruford, she acted in theatrical productions including The Seagull, The Children's Hour, Six Degrees of Separation, Light Shining in Buckinghamshire and The Pentecost.

After appearing in the psychological thriller I Love Your Work, she was cast alongside Jeff Goldblum as the female lead in the NBC television film War Stories.

She next played Alicia Silverstone's wisecracking best friend, Victoria Carlson, in NBC's comedy-drama series Miss Match.

In 2004, Bell appeared in the wrestling film Slammed and made her debut as Sally Heep in the final four episodes of the series The Practice.

In 2008, she played the female lead in the thriller Under Still Waters, for which she won the Newport Beach Film Festival Award for Outstanding Performance in Acting.

She was cast as the lead female role, Dr. Cat Black, in Rob Corddry's satirical comedy Childrens Hospital.

That year she also played Alec Baldwin's wife in the romantic comedy It's Complicated and guest starred in an episode of the fourth season of the series Wainy Days.

Bell was to play Deputy Judy Hicks in Scream 4, but dropped out four days before filming due to scheduling conflicts, with the role going to Marley Shelton.

[23] In 2010, Bell[24] made her writing and directing début with the short film Worst Enemy,[25] which starred Michaela Watkins,[26] Matt Walsh and Lindsay Sloane.

Being an ordinary, unoriginal and unloved woman, she instead becomes so wrapped up in her own quiet neurosis that she finds herself physically stuck in a full body girdle.

(And Other Fair Questions About Marriage), a film she would write and direct, which was eventually renamed I Do... Until I Don't and released in 2017 to mixed reviews.

The couple became engaged on Bell's birthday in March 2012[54] and were married on June 1, 2013, at the Marigny Opera House in New Orleans, Louisiana.