He was among the original cast members of the BBC soap opera EastEnders, playing Nick Cotton, appearing in the first episode in February 1985 and remaining on the show as a recurring character.

Altman was born in Reading, Berkshire, elder son of Cecil Clarkson Stewart (1921–1995), a first-class clerk at the Bank of England, and Tina Florence (1920–2016), daughter of actor Johnnie Schofield.

In 1982, Altman played the role of a Royal Navy rating alongside Timothy Spall in the Channel 4 film Remembrance.

Altman also featured in a 1982 short public information film, "Stupid Git",[5] part of the British government's campaign against drink-driving.

He has had a major role in many famous storylines in the show including the murders of Reg Cox (whose body was found in the first episode) and Eddie Royle, his attempt to kill his own mother Dot by poisoning her and his various feuds with characters including Pete Beale, Den Watts and Mark Fowler.

Both Terry and Nick are the sons of long-running established characters, both are estranged from their mothers, both have committed criminal acts and both have made sporadic appearances on their respective shows.

[11] From late 2010, until early 2011, Altman appeared in adverts for Daz along with actors (Michael Starke and Amanda Barrie), from rival soap opera Coronation Street.

In January 2012, he appeared as one of the first five couples in the third series of Celebrity Coach Trip partnering fellow actor Derek Martin.

In February 2015, he appeared as a guest on The Graham Norton Show as part of an EastEnders special episode alongside June Brown, Adam Woodyatt, Letitia Dean, Danny Dyer, Kellie Bright, Shane Richie, Jessie Wallace and Pam St.