Horowitz has performed on Broadway, including as a replacement in both the 2004 revival of Fiddler on the Roof (as Shandel) and the 2006-2008 run of Les Misérables (joining in 2007 as Cosette and a whore). Her largest Broadway role to date was in the 2011 revival of Sondheim's Follies, as young Heidi, while she played ensemble roles in several Encores! productions (including Annie Get Your Gun). On television, she appeared in the ensembles of The Sound of Music Live! and the 2013 Live from Lincoln Center version of Carousel. Horowitz has lent her voice to commercial jingles.