Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Robert Francis Callahan is a former American football player. He was born in St. Louis, Missouri and attended Beaumont High School where he was the captain of the football and basketball teams. He played college football as a center for the University of Missouri in 1942, but his education was interrupted by two years in the United States Marine Corps during World War II. After being discharged from the Marines, Callahan played football as a tackle and center for the University of Michigan in 1945 and 1946. In January 1947, Callahan announced that he was leaving school and hoped to play professional football. He was drafted by the Chicago Cardinals in the 31st round of the 1947 NFL Draft