It was Roy Huggins who got Garner his big break. Huggins had written a number of Westerns with well thought out scripts and elements of comedy, to include "Buchanan Rides Alone", a Randolph Scott movie that is almost a pilot for "Maverick". Huggins took the "Maverick" concept to Jack Warner, and now the studio found a use for Garner's easygoing persona. Garner was cast as Bret Maverick, professional gambler and coward whose slogan was, "A man who fights and runs away lives to run away another day." For the first three years of the series, Garner worked both the Western and comedy veins in that role.
After some years in the movies, Garner teamed with Huggins again for "The Rockford Files", which was simply Bret Maverick as a private detective in L.A. Garner's knee injuries curtailed the series after seven seasons, and his later TV work wasn't as strenuous, to include the voice of God in "God, the Devil and Bob".
He gets around in a wheelchair these days, and from his appearances on documentaries I suspect he's had a few strokes. He'll be 85 this year.
Good evening, Publius, and thanks for more information about James Garner. ((HUGS))