The son of a glass-worker, Walden attended West Bromwich Grammar School, he then won a major open scholarship to study at Queen's College, Oxford and in 1957 was elected President of the Oxford Union. He completed a postgraduate course at Nuffield College, Oxford, before becoming a University Lecturer.
At the 1964 General Election, Walden was elected Member of Parliament for Birmingham All Saints, later Birmingham Ladywood, in an election where race dominated the Birmingham campaign (see Patrick Gordon Walker). He was re-elected in the subsequent General Elections of 1966, 1970 and 1974 (February and October). He was a campaigner for the liberalisation of the cannabis and gambling laws, even named by some as "the bookies' MP" when he was revealed to be receiving more from the National Association of Bookmakers than from his parliamentary salary.
On 16 June 1977, Brian Walden became Steward of the Chiltern Hundreds, resigning from the House of Commons to become a journalist and broadcaster. He has presented various television programmes, mostly for London Weekend Television, such as Weekend World, The Walden Interview and Walden, and was a member of the board of Central Television between 1981 and 1984.
Walden is considered one of the finest political interviewers in British broadcasting, tenacious and ruthless. He was well-known for his one to one interviews of major politicians, especially Margaret Thatcher. He was said to be her favourite interviewer, although he would give her a tough ride, and she revealed in her autobiography that Walden had been a speechwriter for her.
In November 1989, Thatcher gave Walden a famous interview when her own Party was turning against her. He did not let up on her:
Brian Walden continues to broadcast. In March 2005, he began presenting a ten minute programme on Fridays, called A Point of View, on BBC Radio 4, in a spot formerly occupied by Alistair Cooke's Letter From America.