Lamb was born in Edmonton, Greater London, to Jessie White and Ronald Douglas Lamb, the eldest of four including his brother, Wesley, and a sister. Lamb had a turbulent childhood; he was verbally abused by his father and often had to keep his parents from fighting. In 2011, he participated in the BBC series Who Do You Think You Are? and discovered that he is descended from a line of proprietors of Day's Menagerie and the famous Martini Bartlett lion tamer.
Lamb attended Edmonton County School, and later joined the oil industry, which resulted in him working in Libya and Canada, where he attended St. Francis Xavier University in Antigonish, Nova Scotia. This developed his amateur interest in acting to a professional level, and he performed at Canada's Stratford Festival in 1975–1976. Lamb is distantly related to Edward Buckton Lamb (1806–1869), a Victorian architect who designed St Martin's Gospel Oak and St Mary Addiscombe.
After returning to Britain from Canada, Lamb became a regular cast member, along with Kate O'Mara, in the BBC's North Sea ferry-based soap Triangle (1981–83), in which he played Matt Taylor, the ship's Chief Engineer.
Other credits include The New Avengers, The Professionals, Fox, Minder, Lovejoy, Get Back, A Touch of Frost, Our Friends in the North, Taggart, Casualty, Kavanagh QC, Spooks, Midsomer Murders, and The Bill.
Between 2007 and 2010, Lamb appeared in Gavin & Stacey playing Gavin's father, Michael "Mick" Shipman.
In 2008, Lamb began playing Archie Mitchell, the father of Ronnie and Roxy Mitchell in EastEnders. He based his portrayal of Archie on his own father. He left the show in April 2009 but returned in July the same year, around the same time that Danniella Westbrook returned to her role of Archie's niece, Sam Mitchell. Archie was killed off in a murder storyline at Christmas 2009. In 2009, Lamb starred alongside Liam Cunningham in Blood: The Last Vampire, in the role of General McKee. On 19 February 2010, Lamb appeared with his son, George Lamb, in EastEnders Live: The Aftermath, after Stacey Branning was revealed to be Archie's killer in the closing moments of the 25th Anniversary live episode.
In April 2011, BBC Learning launched "Off By Heart Shakespeare", a school recital contest for secondary school pupils. For the project Larry took on the role of Jaques from the play As You Like It and delivered the speech: "All the world's a stage".
It was announced that Lamb would join the cast of New Tricks as Ted Case in series 12, taking over from Gerry Standing, played by Dennis Waterman.
Lamb's films include Buster and Essex Boys. In 1983, he had a small speaking role in Superman III.
Theatre work includes Educating Rita 'Frank' Dir. Jeremy Sams [Chocolate Factory]; The Five Wives of Maurice Pinder 'Maurice' Dir. Sarah Frankcom [National Theatre]; Fool for Love 'Old Man' Dir. Lindsay Posner [Apollo West End/NIMAX]; The Price 'Victor' Dir. Sean Holmes [Tricycle/Apollo West End/National Tour]; Hamlet 'Claudius' Dir. Steven Pimlott [RSC]; The Prisoner's Dilemma 'The Professor' Dir. Michael Attenborough [RSC]; Art 'Marc' Dir. Rachel Kavanaugh [Wyndhams West End]; Inherit the Wind 'Drummond' Dir. Dan Crawford [King's Head]; Nine 'Guido' Dir. David Leveaux [Donmar]; The Sisters Rosensweig 'Kantlowitz' Dir. Michael Blakemore [Old Vic/Greenwich]; Butterfly Kiss 'Teddy' Dir Steven Pimlott [Almeida]; Lulu 'Rodrigo' Dir. Jonathan Kent [Almeida]; La Musica 'Him' Dir. Joseph Blatchley [Hampstead]; Making It Better 'The Husband' Dir. Michael Rudman [Hampstead/Criterion West End]; A Madhouse in Goa 'Niko/Oliver' Dir. Robert Alan Ackerman [Hammersmith/Apollo West End]; Greenland 'Brian' Dir. Simon Curtis [Royal Court]; Insignificance 'The Ball Player' Dir. Max Stafford-Clark [Royal Court]; Seduced 'Raul' Dir. Les Waters [Royal Court]; Filomena 'The Plumber' Dir. Franco Zefirelli [Lyric West End]; Comedians 'George McBrian' Dir. Mike Nicholls [Music Box/Broadway].
In 2013, Lamb began presenting a regular Sunday morning show on LBC. He is an occasional reporter for the BBC programme The One Show. Lamb took part in Gareth's All Star Choir in 2014, as part of the BBC's Children in Need appeal.
In 2016, he appeared in the sixteenth series of I'm a Celebrity...Get Me Out of Here!.
He became the 6th Celebrity to be voted out of the jungle in the 2016 series. His time in the jungle was marked with his many arguments with Martin Roberts.
Lamb has a daughter Vanessa Lamb (born 1969) with his first wife Anita Wisbey, he is also the father of radio DJ and television presenter George Lamb, from his second marriage to Linda Martin. Lamb recently split up with his partner Clare Burt, with whom he has two daughters: Eloise Alexandra (born 1999), and Eva-Mathilde Lamb (born 2003).
Lamb is sponsoring two young Senegalese girls, Fatou and Oumou, through school.
In 2011, Lamb's autobiography Mummy's Boy was published by Coronet.
Lamb won the award for Best Villain at the 2010 British Soap Awards.Film