She made her Broadway debut as Brenda in Hairspray in 2003, and she later reprised the role in the touring company. Her "big break" came when she originated the character of Lenora and starred in the Broadway musical Cry-Baby for which she won a Theatre World Award and was nominated for a Drama League Award.
From April 17 to October 7, 2007, Mauzey acted as the standby for the lead role of Glinda in the Broadway production of Wicked, covering in the absence of Kendra Kassebaum. She later returned to the company following the closure of Cry-Baby, replacing Kassebaum in the lead role from November 11, 2008. Through her initial contract, Mauzey starred opposite Elphaba actors Marcie Dodd, Nicole Parker and Dee Roscioli. She left at the end of her contract on August 9, 2009 and was replaced by Erin Mackey. She then was reunited with Dodd when the pair reprised their roles in the San Francisco production, appearing from June 29, 2010 until the closing night on September 5, 2010. Mauzey returned once more as Glinda in the show's first national touring production, beginning February 24, 2012, in Tempe, AZ. She replaced Katie Rose Clarke and appeared alongside Mamie Parris and her former Broadway co-star Nicole Parker as Elphaba. She ended her engagement on August 14, 2012 and was replaced by Patti Murin. She then returned to Broadway's Wicked on October 16, 2012 to April 21, 2013, appearing opposite Jackie Burns and Willemijn Verkaik. Mauzey returned to the role for the final time on September 24, 2013 as part of the tenth anniversary cast alongside Lindsay Mendez as Elphaba. Mauzey performed as Glinda in the tenth anniversary performance of the show on October 30, 2013. Her run ended on February 22, 2014. 
Mauzey also played the title character in a concert version of Cinderella, which took place on May 14, 2010 at the Nashville Symphony Orchestra. She played the role of Cinderella again when the concert returned to the Nashville Symphony Orchestra on April 15, 2011 alongside Wicked alum Eden Espinosa, who played the Fairy Godmother. In regional theatre, she appeared in:City of Angels, "Mallory Kingsley", Reprise! LA, California, (2006); The Musical of Musicals (The Musical!), Laguna Playhouse, California (2005); 110 in the Shade, The Pasadena Playhouse, California (2004) She also played Audrey in the St. Louis Muny production of Little Shop of Horrors from July 25-31, 2011.
- "Alli Mauzey Biography". Broadway.com. 2008-11-03. Archived from the original on December 19, 2008. Retrieved 2009-02-21.
- "2008 Theatre World Awards Bring Together Stage Vets and Newcomers, Photo OP: Broadway.com Buzz". Broadway.com. 2008-10-06. Retrieved 2009-02-25.[dead link]
- "Marcie Dodd and Alli Mauzey to Join Cast of San Francisco's Wicked". playbill.com. 2010-06-17. Archived from the original on 19 June 2010. Retrieved 2010-06-19.
- "Wicked Tour Will Welcome Alli Mauzey and Andy Kelso". Archived from the original on 2012-02-20.
- "Katie Rose Clarke Will Return to Broadway's Wicked".
- "The CINDERELLA Files: Alli Mauzey". Broadwayworld.com. 2010-10-05. Retrieved 2010-03-06.
- Eden Espinosa joins cast of Show Hope's second annual CINDERELLA
- Perlmutter, Sharon."Review, City of Angels" talkinbroadway.com, January 29, 2006
- 110 in the Shade, 2004 listing pasadenaplayhouse.org, accessed August 2, 2009
- Alli Mauzey Is Audrey in Muny Little Shop of Horrors; Cast and Creative Team Announced