He was the first employee hired at the NCAA by Executive Director Walter Byers in 1952 and wrote the first manuals for the NCAA basketball tournament and the College World Series. Duke also began the compilation of the elaborate NCAA record books and was a prominent force in cultivating media interest, especially with television. He became commissioner of the Big Eight Conference in 1963 at the age of 34 and moved on in 1971 to become commissioner of the Big Ten. Duke served on the NCAA Men's Basketball Committee from 1975-81, when the tournament expanded from 32 to 40 to 48 teams, meaning teams other than conference champions could get into the field. He was also on the Basketball Television Negotiating Committee at a crucial time for the NCAA as TV money started to reach unimagined numbers.