Before appearing in Hollyoaks, Farnworth appeared on stage in The Lion, the Witch and the Wardrobe[2] and in The London Plays, written by Ed Hime and directed by Kelly Wilkinson.[2] He has also appeared in three episodes of ITV1's 1960s medical drama The Royal, playing a character called Nev Cartwright.[3]
In 2014, he played Florian Dupont, a Belgian refugee, in the TV series Mr. Selfridge before joining the cast of Coronation Street as Andy Carver; his departure was announced in 2016.[6] His last scene, aired on 20 January 2017, saw him being supposedly killed by Pat Phelan (Connor McIntyre).[7] However, on 18 August 2017, Farnworth made an unexpected and unannounced return; revealing that Phelan was in fact, holding him captive in the cellar of an abandoned house until his death on 27 October 2017.[8] In 2019, he has appeared in the TV Series Endeavour, playing the role of PC Rich Potter.
Farnworth joined the cast of Emmerdale in 2024, playing John Sugden. His first episode aired on 7 August 2024.