Lumsden attended Lady Manners School, situated in Bakewell in the Peak District, before he trained at the Guildford School of Acting, graduating in 1986. From 1995 to 2015, Lumsden was married to Actress Sophie Thompson. They have two sons, Ernie James (born 1997) and Walter Eric (born 2000).
He has composed music for cinema, television and theatre, including the Soundtrack to the 2009 film Morris: A Life with Bells On, a full musical score for Alice in Wonderland at the New Vic Theatre in Stoke, title music for The Morning Show (BBC) and incidental music for his brother-in-law Greg Wise's BBC documentary about the life of Jack Good. He has released two albums with his band Henry Kissing Her – A Little of Who You Fancy (1996) & Pull (2006) – and also released a CD of piano music, Concert From The Eyrie (2001). In 2012, Lumsden and John Dipper released the album Sunshine Takes You: 11 songs for ukulele, fiddle, banjo, bass, percussion & keyboards.
He performed his own one–man musical play We Could Be Heroes at the Bridewell Theatre in 2004. His repertory theatre work at Stoke-on-Trent and Basingstoke included Master Harold & The Boys, the title role in Hamlet, As You Like It, King Lear, A Trip To Scarborough, Amadeus, Juno and the Paycock, Far From The Madding Crowd and Having A Ball. He played Roche in Rat in the Skull at Theater Exchange, Minneapolis, and John Thorpe in Northanger Abbey at Greenwich. At the Almeida Theatre, London, in February 2016 he was Cartwright (Telegin) in Chekhov's Uncle Vanya for Director Robert Icke, providing on-stage musical accompaniment to the action on mouth-organ and guitar.
In 2014, Lumsden starred in the independent British feature film Downhill, a comedy about four men attempting Alfred Wainwright's Coast to Coast Walk.
