Ward went to school and made his early athletic mark in Farmington, New Mexico, a small oil and gas city, and one known for its amateur baseball programs. Ward thrived in the American Amateur Baseball Congress-sponsored baseball leagues and graduated from Farmington High School, home of the Scorpions. Ward was drafted out of high school in 1982. Three brothers were also excellent athletes in their own right. Tommy, the oldest, was a baseball player; Gary, the next younger, was a standout wrestler; and Michael was a basketball player. Duane also starred in the Connie Mack World Series, a baseball tournament for 18-and-under players that has been hosted in Farmington since 1965.
Ward became one of the Jays' most dependable middle relievers in 1988, and remained in the role through the 1992 season, when the Blue Jays won their first World Series championship. His pitching repertoire featured a live, mid-90s fastball and a hard slider.
Ward set the Toronto Blue Jays' single-season record for saves with 45 in 1993.
The capstone of Ward's career was the 1993 World Series, in which Toronto repeated as World Champions. Ward earned two saves for Toronto over Philadelphia: in Games 1 (Toronto 8, Philadelphia 5, in Toronto) and in the wild Toronto 15-14 victory in Game 4 in Philadelphia, when Ward got the last four Phillies out after Toronto scored the final six runs of the game. And, Ward was the winning pitcher for the decisive Game 6, when Joe Carter's dramatic three-run walk-off homer was the first home run to end a World Series since Bill Mazeroski's did in Pittsburgh in 1960.
The rest of Ward's career was beset by injuries and he would never save another Major League game after 1993. After missing the entire 1994 season due to bicepstendinitis, he retired from the Toronto Blue Jays after pitching four games during the 1995 season. He finished with a 3.28 ERA and 121 saves.