Manush was born in Tuscumbia, Alabama. He followed his older brother, Philadelphia Athletics third baseman Frank Manush, to the major leagues in 1923 and quickly became known as a skillful hitter. During his rookie season with the Tigers, he batted .334 in 308 at bats while sharing an outfield with Ty Cobb, Harry Heilmann, Bobby Veach, and Bob Fothergill. In 1926, he led the American League with a batting average of .378 and finished second behind Babe Ruth in the statistical categories of slugging percentage (.564) and on-base plus slugging percentage (.985).