Villaseñor was introduced as a featured player on the October 1, 2016, episode of SNL, alongside Mikey Day and Alex Moffat. Her debut was an impression of Sarah Silverman in the Family Feud: Political Edition sketch. Villaseñor is the second Latina cast member after Noël Wells, who is a quarter Mexican, and the first Latina to be promoted to repertory status. She was promoted to the cast of repertory players in season 44. She previously auditioned for the show in 2009. She did several impressions but was not hired. Instead, Nasim Pedrad and Jenny Slate were hired.

Villaseñor was a semi-finalist in season 6 of America’s Got Talent. Previously, she was selected for the New Faces lineup in the 2010 Just for Laughs Montreal Comedy Festival. She has also done voice work for the animated shows Adventure Time, Family Guy and TripTank. Villaseñor appeared on the second season of HBO’s Crashing.

After Villaseñor became a cast member of SNL in 2016, she deleted tweets she had previously written that some viewed as racist. Most of the tweets uncovered by media publications had been posted in 2010 and 2011. Villaseñor wrote tweets such as, “A bossy black lady at my temp looks exactly like steve erkel. Ugly”. SNL and Villaseñor declined to comment on the alleged racist tweets. Villaseñor defended the tweets as “trying to be edgy,” and said she didn’t regret the deletions. In 2018, she told Elizabeth Blair on Weekend Edition Saturday, “I’m flawed like everyone else, and yeah, I just wanted to make sure I was perfect.”

Villaseñor also makes visual art and released her debut album Dreamer in October 2019.