Mario Sean Clark (born March 29, 1954 in Pasadena, California) was an American football cornerback who played for the Buffalo Bills and San Francisco 49ers of the NFL. He played college football at the University of Oregon. Playing for the Bills, Clark was a ballhawk who had 25 NFL interceptions by the age of 27. But Mario Clark managed only one more interception the rest of his career, finishing his NFL career with 26 interceptions.