Olympic Athlete. At seven years of age, he suffered severe burns to his legs from a school explosion in which he lost his older brother. The doctor had wanted to amputate them to save his life, but his mother stopped the doctor and said that she would do whatever it took to save his legs.

He was a student at the University of Kansas when he first came to the attention of the track and field world. He was the national collegiate and AAU (Amateur Athletic Union) country's top amateur athlete champion in 1932. Over the next six years, he earned the nicknames "Kansas Ironman" and "Kansas Flyer" for a series of exceptional performances. A graduate of the University of Kansas, he won two national collegiate titles and eight AAU crowns, including five in the outdoor one mile-1500. In the 1932 Summer Olympics in Los Angeles, he took 4th place in the 1500 meters. In 1933, he won the AAU Sullivan Award for his various running achievements in middle-distance. After losing the 1934 AAU to Bill Bonthron of Princeton, he took the title for the next four years (1935-1938). He was second (silver) in the 1936 Olympics (Berlin) in the 1,500 meters, yet two weeks later, in Stockholm, he set an 800-meter world record of 1:49.7 that would stand for three years. In 1938, he set a world record in the indoor mile run of 4:04.4 (he owned 12 of the 31 fastest mile times on record).

Cunningham earned a master's degree from the University of Iowa and a PhD from New York University. In 1940, after retiring from running, he became a rancher, devoting his time to his youth ranches, which housed abandoned, abused, or delinquent children. He and his wife Ruth operated the Cunningham Youth Ranch in Kansas for over 30 years. He passed away in 1988 in Menifee, Arkansas, after taking in over 9,000 at-risk young people at ranches in Kansas and Arkansas.

In 1961, he was inducted into the Kansas Sports Hall of Fame. In 1974, he was a charter inductee into the National Track and Field inaugural class Hall of Fame, along with other track and field star athletes like Mildred (Babe) Didriksen, Jesse Owens, and Wilma Rudolph. In 1978, he was named the most outstanding track athlete to compete at the Madison Square Garden during its first 100 years. In 1995, he was posthumously inducted into the Cornell College Athletic Hall of Fame.