Stengel was athletically inclined and played various sports in grade school and high school, including baseball, football and basketball. He had no particular vision of sports as a long-term profession, and he had aspirations of a career in dentistry. As described in his autobiography, on pages 58 and 75-76, he saved enough money from his early minor league experience in 1910-1911 to train to become a dentist. He had some problems due to the lack of left-handed instruments and the training was a struggle. Meanwhile, his minor league career picked up, as he was drafted by the Brooklyn Dodgers and spent most of the 1912 season playing for the Montgomery, Alabama, club in the Southern Association. He had "a pretty good year" with Montgomery, batting .290 with a reputation as a good base stealer. He was brought up to the Dodgers late in the season, and baseball soon became his primary occupation.
In 1914 he got in touch with his baseball and football coach from Kansas City, Bill Driver, who was the football and basketball coach at the University of Mississippi. Stengel coached the Ole Miss baseball team to a 13-9 record. This is where he earned the nickname "The Old Professor".
Casey was admitted to Glendale Memorial Hospital in Glendale, California on September 14, 1975 after feeling ill. It was there that he learned he had cancer of the lymph glands. He died there of cancer 15 days later on September 29, 1975. Stengel was interred in the Forest Lawn Memorial Park Cemetery, Glendale, California. His wife, Edna, who he had married in 1924, died three years later and was interred adjacent to him. A plaque at the cemetery reads in part "For over sixty years one of America’s folk heroes who contributed immensely to the lore and language of our country’s national pastime, baseball".The Casey Stengel Plaza outside Shea Stadium's Gate E was named after him, as is the New York City Transit's Casey Stengel Depot across the street from Shea Stadium at the time, and now Citi Field.
A sculpture of Casey Stengel is part of the IUPUI Public Art Collection. The sculpture by Rhoda Sherbell can be found outside of courtyard of University Place.