After working for the BBC World Service for a number of years in the mid to late 1970s he joined Michael Bogdanov at the Young Vic Theatre, London as Press Officer.
These included Good and Bad at Games, the first screenplay written by William Boyd, Michael Bogdanov's adaptation of Hiawatha with the National Theatre, and the Jack Gold's feature The Chain which starred Warren Mitchell, Bernard Hill, Nigel Hawthorne, Billie Whitelaw and Leo McKern.
For the BBC and Masterpiece Theatre, he was Executive Producer of Noël Coward's Star Quality, a series of six plays which starred, among others, Judi Dench, Ian Holm, Susannah York, Ian Richardson, Patricia Hayes, Max Wall, Gary Waldhorn, Nigel Havers and a very young Hugh Laurie.
His many productions in this period included Mike Newell's An Awfully Big Adventure based upon Beryl Bainbridge's novel and starring Hugh Grant, Alan Rickman and Prunella Scales; an adaptation of C. P. Taylor's And a Nightingale Sang with Joan Plowright and Stephen Tompkinson and which won the Prix Europa and Malcolm Bradbury's Silver Nymph-winning The Gravy Train and The Gravy Train Goes East with Ian Richardson, Francesca Annis and Oscar winner Christoph Waltz.
Other productions included Christopher Hampton's Total Eclipse starring Leonardo DiCaprio and David Thewlis, the mini series Friday on my Mind starring Christopher Eccleston for BBC1 and an adaptation of Rosamunde Pilcher's September which featured Jacqueline Bisset, Jenny Agutter, Mariel Hemingway and Paul Guilfoyle.
He was co-producer of Underdogs aka Metegol directed by Academy Award winner Juan Jose Campanella.
The film was released in Argentina in July 2013 by Universal Studios and attracted an audience over more than two million people.
King and his son Phin is a film producer who has worked with David Tennant and Elisabeth Moss on a movie about R. D. Laing.