Williams made her acting debut in a non-speaking role in the 1993 drama
Indian Summer, which also featured her sister Kimberly. She then spent from 1994 to 1996 playing teenage
Danielle Andropoulos on the soap opera
As the World Turns. Williams starred in the television series
Good Morning, Miami (2002–2004). Since then she has also appeared in episodes of
Psych,
How I Met Your Mother, multiple episodes of
E-Ring, multiple episodes of
Huff,
Law & Order: Special Victims Unit, multiple episodes of
Side Order of Life,
The Mentalist,
Monk,
CSI: Crime Scene Investigation,
Royal Pains, multiple episodes of
Saving Grace,
Love Bites,
The Protector,
Retired at 35, and multiple episodes of
Warehouse 13. Williams also had a guest-starring role on
American Dreams, playing singer
Sandie Shaw and performing Shaw's 1964 hit "
(There's) Always Something There to Remind Me" on
American Bandstand. In 2007, she starred in the
Off Broadway play
Burleigh Grime$ and appeared as Victoria, a cupcake baker, on six episodes of the television series
How I Met Your Mother; a role she reprised in the concluding seasons of the show. In 2010, she starred in the made-for-TV
Lifetime movies,
Patricia Cornwell's
The Front and
At Risk, which premiered on the channel on April 17, 2010. In 2011 and 2012, she played the role of Claire in a film adaptation of
Something Borrowed opposite
Kate Hudson,
John Krasinski, and her college roommate
Ginnifer Goodwin, and she also reprised her role as Victoria on
How I Met Your Mother. She made her Broadway debut in
John Grisham's
A Time to Kill playing law student Ellen Roarke, on September 28, 2013, with the opening night on October 20, 2013. She had previously worked at the Williamstown Theater Festival, and also worked as the understudy for both
Rachel Weisz and
Gretchen Mol opposite
Paul Rudd in the world premiere Off-Broadway production of
Neil LaBute's play
The Shape of Things. She performed both lead female roles multiple times during the run. In 2015 and 2016, Williams starred as a fictionalized version of comedian
Jim Gaffigan's real life wife in
The Jim Gaffigan Show on
Comedy Central, a sitcom about a couple raising their five young children in a two-bedroom New York City apartment which also starred
Michael Ian Black and
Adam Goldberg. She wrote, directed, and starred in a short film,
Meats, about a pregnant vegan who wrestles with her newfound craving for meat. It was shown at the
Sundance Film Festival in January 2020. ==Personal life==