In 2001 he released a highly regarded autobiography So You Wanna Be A Director? published by Tomahawk Press (ISBN 0-953 1926-5-2). Considered "a classic among directors' autobiographies" it has forewords by both Richard Attenborough and Mike Leigh. In their review, the Directors Guild of America stated

His career spanned half a century, beginning in the early 1940s and ending in 2002. His career peaked in the 1960s with large-scale adventure films and in all he directed nearly 50 pictures.

Injured in the Liverpool Blitz, he joined the RAF Film Unit, where he worked as camera operator on propaganda films for the Ministry of Information and the British Council. We Serve (1942), a recruiting film for women, was directed by Carol Reed, who made Annakin his assistant Director, after which Annakin directed several training films for Verity Films, a group led by Sydney Box, who was about to become head of Gainsborough Pictures. His early documentaries included London 1942 (1942), Make Fruitful the Land (1945), We of the West Riding (1945), and English Criminal Justice (1946). He also made the shorts It Began on the Clyde (1946) and Fenlands (1946).

Annakin had made a number of documentaries for Sydney Box and when Box took over as head of Gainsborough Pictures he brought Annakin with him and assigned him to his first feature, Holiday Camp (1947). It was a solid hit and launched Annakin's career.

Holiday Camp featured the Huggetts, a working-class family living in suburban England headed by Jack Warner and Kathleen Harrison. They were spun off into their own vehicle directed by Annakin, Here Come the Huggetts (1948) with Petula Clark, Jane Hylton, and Susan Shaw as their young daughters, Amy Veness as their grandmother and Diana Dors as their cousin. It was popular and led to Vote for Huggett (1949) and The Huggetts Abroad (1949).

Annakin moved over to Associated British Pictures Corporation for whom he directed Landfall (1949), a war film; and Double Confession (1950), a thriller.

For United Artists he did the comedy Hotel Sahara (1951) with Peter Ustinov.

Annakin then received an offer from Walt Disney to make The Story of Robin Hood and His Merrie Men (1952) with Richard Todd. He then made an action film set during the Malayan Emergency, the United Artist's film The Planter's Wife (1952) with Jack Hawkins and Claudette Colbert, which was a big hit in Britain. Disney reunited Annakin and Todd on The Sword and the Rose (1953), a commercial disappointment.

Annakin made a comedy, You Know What Sailors Are (1954) then did another imperial adventure story with Hawkins, The Seekers (1954). He returned to comedy for Value for Money (1955), Loser Takes All (1956) and Three Men in a Boat (1956). The latter especially was popular.

Annakin made Across the Bridge (1957) with Rod Steiger from a story by Graham Greene. He then travelled to South Africa to make another adventure story, Nor the Moon by Night (1958).

Disney called again and hired Annakin to make a mountaineering tale, Third Man on the Mountain (1959). They kept him on for Swiss Family Robinson (1960), which Walt Disney’s nephew, Roy, considered "one of the greatest family adventure films of all time and a favourite for generations of moviegoers". It was a huge hit.

Annakin returned to comedy with Very Important Person (1961) and travelled to South Africa for The Hellions (1962). The Fast Lady (1962) and Crooks Anonymous (1962) were other comedies.

He was later associated with another American Producer, Darryl F. Zanuck, when he was hired to direct the British and (uncredited) French and American interior segments in The Longest Day (1962), which was nominated for an Academy Award for Best Picture, eventually losing out to Lawrence of Arabia. Annakin then made The Informers (1963).

As head of the 20th Century-Fox Studio, Zanuck endorsed Annakin's most ambitious project Those Magnificent Men in their Flying Machines (1965), also co-written by Annakin for which he received an Academy Award nomination.

Annakin also directed the big-scale war film Battle of the Bulge the same year for the Warner Brothers studio. He did The Long Duel (1967) in India for Rank, The Biggest Bundle of Them All (1968) for MGM in Italy, and Monte Carlo or Bust (1969) for Paramount Pictures.

Annakin continued to travel widely with his films The Call of the Wild (1972) was shot in Finland; Paper Tiger (1975) in Malaysia;

In 1979, Ken Annakin left Britain and moved to Los Angeles. There he made The Pirate (1978) and Institute for Revenge (1979). He travelled to Europe for The Fifth Musketeer (1979). In Hollywood he made Cheaper to Keep Her (1981) and went to Australia for The Pirate Movie (1982).

Annakin's last completed film was The New Adventures of Pippi Longstocking (1988). The 1992 project Genghis Khan was not completed.

Annakin was made one of the few Disney Legends by the Walt Disney Company in March 2002. He is only the second film Director to be so honoured. He was also awarded an OBE the same year for services to the film industry and received an honorary Doctor of Letters degree from Hull University.

Claims were made that George Lucas took the name for Anakin Skywalker in Star Wars from his friend and fellow film director; however, Lucas' publicist denied this following Annakin's death in 2009.