[2][non-primary source needed] Machin started his career in retailing as a teenage shelf stacker at a Sainsbury's Savacentre in Hempstead Valley Shopping Centre outside Gillingham, Kent.
[3] He then became CEO of Steinhoff International in the UK before being headhunted to join Marks & Spencer (M&S) as managing director of its food division.
[11] In August 2022, Machin said that London's Oxford Street was in danger of becoming a "dinosaur district destined for extinction", and has been vocal in support of the controversial planned demolition and redevelopment of M&S's flagship store there, close to Marble Arch.
[12][13] Machin has advocated for reforms to the apprenticeship levy, arguing that its current structure hindered M&S's ability to train more young individuals.
[16] Machin lives in south London, and his hobbies are music, theatre, politics, food, fashion, and walking his dog, Kostas.