The basketball player with the most championships is Bill Russell, who won 11 NBA titles in his 13-year career with the Boston Celtics.
Russell's championships with the Celtics were in 1957, and then an unprecedented eight consecutive titles from 1959 to 1966, followed by two more in 1968 and 1969. He also won two NCAA championships and a gold medal in the 1956 Summer Olympics, making him one of only eight players to achieve the Triple Crown in basketball.