She is best known as Alex Dunphy in the TV series Modern Family for which she, along with the rest of the show's cast, won three Screen Actors Guild Awards for Best Ensemble in a Comedy Series
Winter obtained her first entertainment industry job in a Cool Whip commercial at age six. She had her first television role at age 7, in an episode of Listen Up!, and followed it with appearances in a variety of shows such as Tickle U, Freddie, Monk, Bones and ER.
In the animated children's show Phineas and Ferb, she voiced the character of Gretchen before winning the regular role of Alex Dunphy in the series Modern Family, which premiered in 2009. She has continued to work in TV animation, including providing the voice of Marina the Mermaid on Disney Junior's Jake and the Never Land Pirates and Sofia the First.
Winter has appeared in feature films, most notably in Kiss Kiss Bang Bang and also Speed Racer, Duress, Opposite Day and Fred 2. For her leading role in the film The Chaperone, she was nominated at the Young Artist Awards 2012 as Best Actress in a Motion Picture.
She also lent her voice to characters in the animated films Bambi II and Ice Age: the Meltdown. In 2012, Winter was cast as Sofia, the lead character in a new Disney animated franchise Sofia the First. The series premiered in January 2013 on Disney Junior. Winter has made a video cover of Taylor Swift's "I Knew You Were Trouble", uploaded on YouTube January 23, 2013.
Previously, Winter and singer-songwriter Jackson Guthy made two video covers, Gotye's "Somebody That I Used To Know" and Owl City and Carly Rae Jepsen's "Good Time", which garnered over 140,000 views on YouTube within the first ten days of release. Winter reprised her role as Dora The Explorer in a three-part parody mini-series by website College Humor.