Felix Leiter is a fictional male in the James Bond, 007 series. The character was portrayed on screen by Jack Lord, Cec Linder, David Hedison, Jeffrey Wright, John Terry, Norman Burton, Rik van Nutter. His allegiance / loyalty is to the C.I.A.. Felix Leiter is the C.I.A.'s contact to James Bond. James Bond first meets Felix whilst they are both trying to beat Le Chiffre in Casino Royale. Felix provides James with the information he needs and never gets involved in the action. In Casino Royale, Felix provides the necessary money to keep James Bond in the game against Le Chiffre to bankrupt the terrorist financier. Felix is reoccurring character and unlike M does not appear in every film, just the odd guest appearance.
In Licence to Kill, Franz Sanchez, a drug baron from the fictional country of Isthmus has Felix punished by being fed to the sharks and loosing his leg. Also in Licence to Kill, Franz kills Felix's new wife to emotionally torture Felix. In the books, Felix Leiter lost his leg in a shark attack in Live and Let Die. Felix was supposed to die in the book but after protest about what happened to the character and maybe how it would affect the sales in the United States, Felix wasn't killed off but he did loose his leg and arm. Felix was no longer of use to the C.I.A. and so left the service. Leaving the service didn't mean he was no longer part of the stories, he came back as a private detective still assisting James Bond.
In the first television production of Casino Royale, the roles are reversed, true the main character is still James Bond but is referred to as Jimmy Bond and is a C.I.A. agent. Felix Leiter is a British agent working on behalf of M.I.6.. The plot is still the same, just the roles swapped. When the big movie productions began of James Bond, the roles returned back to how they were in the books.
Jack Lord played the first Felix Leiter in Dr. No but then dropped out of future films because he didn't want to be a bit character, he wanted a more substantive role in the film which the producers weren't willing to give him. Since then the films have generally had a different actor play the role of Felix Leiter but David Hedison and Jeffrey Wright have played the character more than once.
In the films, James Bond first comes into contact with Felix Leiter in Dr. No but in the books, the first contact was in Casino Royale.
When the films were re-booted with Daniel Craig playing the eponymous hero, they also bought in someone new for the role of Felix Leiter. The person who undertook the role was Jeffrey Wright. Felix first introduces himself at the casino where James has lost all his money and is planning on just killing Le Chiffre. Felix Leiter tells James to play it cool and that the C.I.A. will give him the necessary funds to beat Le Chiffre.
Jeffrey Wright returned as Felix Leiter in the follow up in Quantum of Solace which although based on a James Bond book title, it was a new story. Felix had been promoted to Central America where he was helping his colleague to do a deal with