[3] He gained an Exhibition in English Literature as well as a choral scholarship to Clare College, Cambridge, where he studied under John Rutter and joined the Footlights.

[3] Hesketh-Harvey worked as a staff producer for the BBC-TV Music and Arts Department, joining in 1980 and leaving to write the script for Merchant Ivory's Maurice (1987).

[3] He won the 1988 Vivian Ellis Award for musical-theatre writers and subsequently studied with Stephen Sondheim, who had been appointed to the Cameron Mackintosh visiting professorship in Contemporary Theatre at St Catherine's College, Oxford.

Hesketh-Harvey wrote and sang with pianist Richard Sisson for over 30 years, as a musical comedy duo Kit and The Widow, "showcasing his tart, precisely observed and witty style, delivered with exquisite pronunciation and perfect timing".

[7] Hesketh-Harvey starred in the 1996 production of Salad Days at the Vaudeville Theatre, and in Tom Foolery (Jermyn Street and national tour).

He co-starred with Tim Minchin in the first BBC Comedy Prom at the Royal Albert Hall in 2011: the last time that Kit and the Widow appeared on stage together.

[12] In Spring 2015, Hesketh-Harvey appeared alongside Juliet Stevenson as a guest in Janie Dee's Dream Queen as part of the London Festival of Cabaret in the Sam Wanamaker Playhouse at Shakespeare's Globe.

In 2018 he cooperated with Dutch actor and playwright Jon van Eerd [nl] on a musical comedy based on Charley's Aunt.

His libretto to Anthony Bolton's The Life and Death of Alexander Litvinenko received its first staging at Grange Park Opera in July 2021.

[1][22] Kit Hesketh-Harvey's life and legacy were featured in The Times and The Telegraph, with a heartfelt piece written by British radio presenter and journalist Libby Purves.