His acting credits include Sid and Nancy (1986), Hope and Glory (1987), Rob Roy (1995), The Jackal (1997), Trial & Retribution (1997–2009), Legionnaire (1998), Ordinary Decent Criminal (2000), Vertical Limit (2000), The Tailor of Panama (2001), Flood (2007), The Boy in the Striped Pyjamas (2008), The Paradise (2012), Taboo (2017), Our Ladies (2019), The Nest (2020), Bull (2021), and Andor (2022).

[1] Despite having no family history of acting, he heeded advice from a local amateur dramatics group to apply for a position at the Royal Scottish Academy of Music and Drama in Glasgow.

On television, He gained national prominence playing the role of the notorious Barlinnie Prison convict turned sculptor, Jimmy Boyle, in the tv movie A Sense of Freedom (1981).

His long list of film credits include appearances supporting Gary Oldman in Sid and Nancy (1986),[3] Bruce Willis in The Jackal (1997),[3] Kevin Spacey in Ordinary Decent Criminal (2000) and Pierce Brosnan in The Tailor of Panama (2001).

[7] In March 2014, Hayman presented a BBC Two documentary exploring how shipbuilding industry along the river Clyde and four resulting ships; Cutty Sark, CS Mackay-Bennett, CSS Robert E. Lee and HMS Hood helped shaped up the Commonwealth.

[9] In November 2018, Hayman presented a BBC One documentary telling the story of Captain Jack McCleery and his role, alongside his colleagues, in pioneering Royal Navy's naval aviation with their trial flight on HMS Furious and the subsequent Tondern raid.

[12] In 2001 he founded the humanitarian charity Spirit Aid which is dedicated to children of the world whose lives have been devastated by war, genocide, poverty, abuse or lack of opportunity at home and abroad.

Hayman is currently Head of Operations of the charity which undertakes humanitarian relief projects from Kosovo to Palestine, Guinea-Bissau, Afghanistan, Sri Lanka, Cambodia, Malawi and South Africa.