During the 1928 football season, he rushed for 1,349 yards, scored 103 points, and became the first player from Colorado to receive first-team All-American honors.

Clark played professionally in the National Football League (NFL) with the Portsmouth Spartans / Detroit Lions for 7 seasons from 1931 to 1938.

In 1917, when Dutch was 10 years old, the family moved approximately 60 miles to the west to Pueblo, where the father was employed as a locomotive fireman on a steam railroad.

[10] He was named captain of the basketball team for the second consecutive year, played at the center position, and was selected as an all-conference player.

[11] According to an account published in 1980, Clark earned all-state honors in football and basketball and set South Central League track & field records in the discus and high hurdles.

At the end of the 1928 season, he was selected by the Associated Press as the first-team quarterback on the 1928 College Football All-America Team.

[3][23] In December 1932, United Press sportswriter George Kirksey rated Clark as the greatest football player of the past 10 years.

Then, in March 1933, he surprised followers of the professional game by announcing that he would not return to the NFL in 1933, having elected instead to serve as the head football coach for the Colorado School of Mines.

[25] Clark signed with the Detroit Lions in May 1934 and joined the team for training camp at the end of August.

Clark was the quarterback for the 1934 Detroit Lions team that compiled a 10–3 record and finished in second place in the NFL West behind the undefeated Chicago Bears.

[3] At the end of the 1934 season, Clark was selected as the first-team All-Pro quarterback for the third time in three years playing in the NFL.

[32][33] In the 1935 NFL Championship Game, Clark had "a sensational 42-yard dash" for a touchdown in the second quarter, as the Lions defeated the New York Giants, 26–7.

[34] On January 1, 1936, Clark led the Lions to a 33–0 victory over an all-star team in the first professional football game played in Denver.

"[36] The Los Angeles Times noted that Clark "has been acclaimed as the greatest back in the history of the game.

"[37] Another writer said he had "the nimblest legs in football" and called him the modern back who comes "nearest to perfection".

"[38] Red Grange called Clark "the hardest man in football to tackle" and noted: "His change of pace fools the best tacklers.

[39] He took a job as the general manager of the Colorado State Fair, but wrote to the Lions in June advising that he had been granted a leave of absence to rejoin the club in August, with time to prepare for the Chicago College All-Star Game set for September 1.

Before a capacity crowd of 26,000, the Lions presented Clark with an automobile, and his wife received a platinum wristwatch set with diamonds.

"[45] Tod Rockwell of the Detroit Free Press wrote that, as Clark announced his retirement, he was "bruised from head to foot", his left hand was "swollen double its normal size", there were "welts on his legs, a lump over one eye, and a belt on the mouth had split open his lips in several places.

[48] Bill Shepherd took over as the club's starting quarterback in 1938, and Clark appeared only briefly in six games, carrying the ball seven times and completing six of 12 passes.

Under his leadership, the Lions compiled identical 7–4 records and finished in second place in the NFL's West Division in both years.

In January 1940, after the Lions were sold to new owners, the club agreed to grant Clark a players' release if he submitted a request.

[59] After the war, Clark continued to work in the insurance business and acquired an ownership interest in a wine merchant in Colorado Springs.

[62][63] In March 1949, Clark was hired as backfield coach for the Los Angeles Dons of the All-America Football Conference.

[66] In March 1950, Clark was hired as an assistant coach of the University of Detroit Titans football team.

In February 1951, Clark was promoted to the dual role of head football coach and athletic director at the University of Detroit.

[95][96] After retiring from football in the 1950s, Clark lived in Royal Oak, Michigan, and worked as a sales representative for an engineering firm.