Caissie is an Olivier and Grammy Award nominated veteran of eight Broadway shows and three West End productions. She earned an Olivier Award nomination for Best Actress in a Musical for creating the role of Diana in the UK premiere of Next To Normal, a performance she is currently reprising in the West End through Sept 21, 2024. In October 2024, Caissie will be starring in Ragtime and New York's City Center Encores series.

Broadway credits include originating the role of Elsa in Disney's Frozen; Tom Stoppard's Tony winning Leopoldstadt; Rose in the Tony nominated revival of Caroline, or Change (Grammy nomination); Sheila in the Tony winning revival of Hair (& West End); Molly in Ghost (& West End); Fantine in Les Miserables; Elphaba in Wicked; and Penny in Hairspray. Off Broadway credits includeThe Bedwetter; First Daughter's Suite; and Murder Ballad. 

Caissie has recorded five original cast albums and one solo record. She has performed on the Tony awards four times, headlined Carnegie Hall twice, sung backup for Sir Rod Stewart’s Las Vegas residency, and has played solo to sold out crowds in London, Los Angeles, and New York