Lee Majors was the other brother, his first credited film appearance.  Roger Ewing was the brother that was shot in the leg and shows up in later shows and becomes sort of a deputy.  Roger Ewing is still alive and is living in Morro Bay, CA.  Buck Tayor (Newly) is still alive too.

Later famous stars such as Bette Davis,Slim Pickens Jodie Foster, June Lockhart, Buddy Ebsen,Willaim Shatner,Lesley Ann Warren Kay Lenz,Andy Devine,William Hopper, Rory Calhoun, John Astin, Leonard Nimoy, Kurt Russell,Ed Asner,Robert Culp, Barbara Eden, Angie Dickinson,Gary Busey,Ron Howard,Alan Hale Jr., Harrison Ford, Sam Elliot,Charles Bronson,David Carradine.James Doohan, and others I've missed.