Walter Tenniel Evans was born in Nairobi, Kenya. His middle name derived from the illustrator Sir John Tenniel, a distant relation. His daughter, Serena Evans, is an actress, and his son, Matthew, is a television director.
Tenniel Evans was a direct descendent of Isaac Evans, brother of George Eliot (born as Mary Ann Evans).
Educated at Christ's Hospital, the University of St Andrews and the Royal Academy of Dramatic Art, Evans is best known for his long-running role as Leading Seaman "Taffy" Goldstein (plus other occasional characters) on The Navy Lark, a popular BBC comedy radio series of the 1950s, which starred Jon Pertwee, with Ronnie Barker, Richard Caldicot and Leslie Phillips. Pertwee became one of Evans' best friends – he encouraged Pertwee to audition for Doctor Who, although both were unaware that Pertwee was already being considered for the role; Pertwee subsequently helped Evans get cast in the Doctor Who story Carnival of Monsters.
Frequently cast as a policeman, doctor or priest (he was in fact latterly ordained as an Anglican priest in real life), Tenniel Evans appeared in many of the most popular and successful British TV series of the late 20th and early 21st centuries, as well as many one-off programmes, over a period of 44 years. His TV debut was in the series No Hiding Place in 1960; shortly after this he played Jonathan Kail in Tess, the 1960 ITV adaptation of Thomas Hardy's Tess of the D'Urbervilles, which also featured Geraldine McEwan and Jeremy Brett.
Among Evans' most notable TV credits are The Forsyte Saga (1967), The Saint (1967), four appearances in The Avengers between 1961 and 1968, Softly Softly, (1966, 1969), Randall and Hopkirk (Deceased) (1969), A Family at War (1970), Paul Temple (1970, 1971), multiple appearances in Z-Cars between 1963 and 1972, a regular role in Big Breadwinner Hog (1969), The Liver Birds (1972), The Fall and Rise of Reginald Perrin (1976), Yes Minister (1980), Coronation Street (1980), Rumpole of the Bailey (1983), The Citadel (1983) and "The Dancing Men" (1984), an episode of the Granada series The Adventures of Sherlock Holmes that reunited him with Jeremy Brett.
In 1985 Evans was ordained as a non-stipendiary priest of the Church of England and he retired from stage acting, although he continued to perform in TV programmes until shortly before his death and during that year he had a recurring role in the comedy Shine on Harvey Moon. In 1987 he had a recurring role in the children's sci-fi series Knights of God (1987), which is notable as the last screen credit for Patrick Troughton. Coincidentally, Evans then took over the role of Perce, the grandfather, (originally played by Troughton) in the comedy series The Two of Us following Troughton's sudden death in March 1987.
Evans' TV credits from the late 1980s to 2004 include Inspector Morse, Lovejoy, September Song, Peak Practice, The Bill, Pie in the Sky, Heartbeat, Hetty Wainthropp Investigates, Casualty and Dalziel and Pascoe. His final screen appearance was in an episode of the romantic comedy series William and Mary (2004), directed by his son Matthew, which also co-starred Martin Clunes (who, coincidentally, is the nephew of Evans' colleague Jeremy Brett).
Evans made few appearances in films. His most prominent parts were as a murderous teacher in Walk a Crooked Path (1969), and as a detective in the thriller 10 Rillington Place (1971), the film about the infamous British serial killer John Christie starring Richard Attenborough.Only Two Can Play (1962) - Kennedy (uncredited)
The Wild and the Willing (1962) - Warden (uncredited)
Walk a Crooked Path (1969) - John Hemming
10 Rillington Place (1971) - Police: Det. Sergeant
Knots (1975) - Tenniel - The Director