Regner was born and raised in the Baton Rouge area, the daughter of Jan and Donald Regner, a businessman. She has a sister, Lauren Regner, who is also a performer. She is a graduate of Parkview Baptist High School, and the Louisiana State University with a degree in theatre. In college she was a member of a sorority. In Baton Rouge she has performed at the Theatre Baton Rouge in productions of Rent as Maureen and The Producers. While a student as LSU she performed in the musical Spring Awakening. In 2010 she played the role of Crystal in Little Shop of Horrors at the Ascension Community Theatre.
She performed in the musical Spank, a spoof of Fifty Shades of Grey, in 2014. Regner also performed in Bronies: The Musical, a show about My Little Pony. Regner played the role of Nadia in the pop-opera Bare in Los Angeles and she played the role of Cecile Caldwell in a musical version of Cruel Intentions. She recently played the role of Amy in Company at the Cabrillo Music Theater. Regner performed in the show American Idiot in Los Angeles in 2015.
Regner and Pitch Perfect co-star Kelley Jakle performed in a special concert titled Total Vocal at Carnegie Hall in March 2015.