A Hammers legend, Trevor made 626 league and cup appearances and scored 102 goals in a career that spanned 19 years, between 1965 and 1984. He won 47 full England caps during that time. A highly successful and respected radio and television pundit for BBC Radio and TV, Trevor is the current chair of Sport England.
He will take up his appointment at the beginning of next month. West Ham United Chairman Terence Brown said: "I'm delighted Trevor has agreed to join the Board. His vast knowledge of West Ham United, its culture and history, and his immense football experience, make him uniquely qualified to become the Club's first former player to become a Director.
"The Board includes a chartered surveyor, chartered accountant, banker and a solicitor, now we have appointed one of the most respected and influential figures in football.
"At a time when our players' wages exceed £24million per annum (estimated seventh highest in the Premiership) and our gross transfer spending over the last seven years has exceeded £70million, Trevor Brooking's expertise is clearly essential to our business.
"Being situated in Europe's largest redevelopment area, building what is shortly to become London's second largest football stadium and with an annual turnover forecast to exceed £50million next season, our Club has almost unlimited potential.
"It is vital we realise that potential and I am certain Trevor's appointment will go a long way to ensuring that happens."
Trevor's duties as a non-executive Director will not be confined to football. He will have the same responsibilities as the other Directors and will play an active role in the administration and development of all areas of the Club.
Trevor Brooking CBE said: "I am obviously flattered and honoured to become the first former player in West Ham United's history to be invited on to the Board.
"Naturally from the Club's point of view and with the size of their business, someone with a football background is important as a link between the Boardroom and training ground.
"As a former player and West Ham United supporter myself, I'll be also pleased to reflect the views of the fans and do my best to help the Club move forward to the next stage of its future development."
New team-manager Glenn Roeder said: "When Chairman Terence Brown first told me that Trevor was considering his offer to join the Board I was delighted and 100 per cent behind the idea.
"I'm sure over the coming months Trevor will prove a great help to me and the Club at all levels and I'm looking forward to working with such a highly-respected football personality."
*An exclusive interview with Trevor will appear on the site shortly.