She appeared as Baby June in Gypsy at the Forum Theatre in Wythenshaw, Manchester which starred Josephine Blake, directed by Howard Lloyd-Lewis and choreographed by Paul Kerryson.

[6] She spent two years in Starlight Express at the Apollo Victoria Theatre playing the roles of Buffy, Dinah and Pearl.

In 1998 Casey fulfilled a lifelong ambition by playing Anita in West Side Story, both at the Prince Edward Theatre and on the national tour.

[citation needed] Casey made her first appearance in Chicago as Velma Kelly in 1998, a role she has reprised on numerous occasions.

[10] She originated the role of Dot in the London revival of Sunday in the Park with George at the Menier Chocolate Factory in 2005, but left before the production transferred to The West End and Broadway, being replaced by Jenna Russell.

From July to September 2015 Casey played the role of Lottie in a revival of musical Mack & Mabel at Chichester Festival Theatre.

[citation needed] In January 2018, it was announced that Casey would play the role of Annie in the UK tour of Calendar Girls, which was due to open at the Leeds Grand Theatre in August 2018.

[citation needed] In 2023 Casey was in the new Robert J. Sherman West End musical Love Birds showcase directed by Ian Talbot OBE.