His first job was at Red Rose Radio (now Rock FM) in Preston in 1987, where, even then, he used to occasionally read the weather in the voice of Frank Bruno.

He did voice-over work, then was catapulted to prominence with Spitting Image, where he voiced around forty characters, including John Major in the 1990s, who was then the Prime Minister.

Culshaw rose to fame in January 1998 while working with Steve Penk on Capital Radio, by impersonating William Hague and succeeding in contacting Number 10 Downing Street.

[4] Between 2001 and 2002, Culshaw hosted a programme on ITV called Alter Ego, where he interviewed male celebrities in their own style of speaking, a form of simultaneous translation.

In the same year, he also appeared in the BBC General Election coverage, in the guises of Tony Blair and George W. Bush.

In November 2007 and December 2008, Culshaw, a keen amateur astronomer, appeared on The Sky at Night impersonating a young Sir Patrick Moore.

[citation needed] In February 2021, Culshaw appeared on Celebrity Mastermind, doing "Doctor Who – the Jon Pertwee Years" for his specialist subject.

Some of Culshaw's most famous impressions include former British Prime Ministers Tony Blair and Boris Johnson, Obi-Wan Kenobi (as portrayed by Alec Guinness), Russell Crowe, Presidents George W. Bush and Donald Trump, Ozzy Osbourne, comedian Michael McIntyre, presenter Dale Winton, newsreader Brian Perkins, Sir Patrick Moore, Tom Baker and Les Dawson.

This first came to fruition with his impersonation of Tom Baker's Fourth Doctor for both the TV and radio versions of Dead Ringers.

In the latter, he got to perform his Tom Baker impression "for real" (voicing tape recordings of the fourth Doctor), although his nominal part was that of Earl Rivers.

[13] In March 2019, Culshaw sat for British impressionist artist Sherree Valentine-Daines for a portrait painted to mark the opening of the Clarendon Fine Art Gallery in Hampstead, London.