Also joining will be former Betfair chief executive Stephen Hill as the broadcaster attempts to beef up the commercial and digital expertise of its board.
All three appointees have already received the green light by media regulator Ofcom and will hold their posts for three years.
Lord Puttnam will take the role of deputy chairman from February, replacing Barry Cox, who is stepping down after seven years in the post, while Fox and Hill take non-executive director roles and replace former Channel 5 chief executive Ian Ritchie and former Emap head Sir Robin Miller, who are also stepping down.
Luke Johnson, Channel 4 chairman, said: "The pedigree of our new non-executive directors must be apparent to everyone. They combine proven business experience and knowledge of digital technology with a track record of championing both innovation and creative excellence."
Of the three, Lord Puttnam will be the most familiar to the wider media community, having spent 30 years in the film industry and leading opposition in the House of Lords to cross-media ownership during parliamentary debates surrounding the Communications Act two years ago.
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