Roache was later educated at the independent Rydal School in Colwyn Bay, North Wales. In 1953, he was commissioned into the Royal Welch Fusiliers. He was promoted to Lieutenant in 1954 and left the Army three years later. Due to a mortar bomb explosion that he witnessed while on National Service with the British Army during this time, Roache suffers from tinnitus.
Roache is the second-longest continuous actor in the history of television serials. Only Don Hastings, who has played Bob Hughes on the American soap opera As the World Turns since October 1960, without a break, has played the same character longer. The Guinness Book of Records states that the non-continuous record is held by Helen Wagner, who has played Nancy Hughes on the same soap opera, As the World Turns, since April 1956. Wagner made only sporadic appearances between 1981 and 1985.
In 1992, The Sun newspaper accused Roache of being as boring as his character Ken Barlow. Roache then sued for libel, employing Peter Carter-Ruck as his lawyer. The Sun offered to settle out of court for £50,000. Roache turned this down and went ahead with legal action. He won the case and was awarded the same amount in damages. However, because he had turned down the earlier settlement he was liable for his considerable costs. Roache then sued Peter Carter-Ruck for misadvising him and lost. In 1999, he declared himself bankrupt.
In September and October 2005, Roache appeared as a celebrity contestant in Ant & Dec's Gameshow Marathon. He was the winner of The Golden Shot remake, progressing through to Bullseye where he was beaten by television presenter Vernon Kay.
Roache is now patron of the Ilkeston-based production company Sustained Magic Ltd. The company exists to help encourage the arts development within Ilkeston and the East Midlands to help develop new actors.
In March 2007, Roache was awarded an honorary doctorate by the University of Chester in recognition of his contribution to television. In June of that year, he accepted an offer to become an honorary member of the voting panel for the 'Carer of the Year Award' organised by Castle Comfort Stairlifts of Staffordshire.
Roache is left-handed.