after a brief stint at jarvis christian, he then coached football, basketball, and baseball at bishop. he first came to the attention of southern university officials after one of his texas college teams soundly defeated southern in a game; afterward, when a southern dean accused his texas college players of stealing from the school, mumford forced all of his players to get off of the team bus and to display their personal belongings until the school's missing items could be located. southern officials were impressed by both his coaching and disciplinary actions of that day. once at southern he was also known for emphasizing the importance of education. on the field itself he earned a reputation for perfectionism, making the team practice the same play late into the night to get it just right, even employing a white-colored football to assist visibility during late night use. he was also notably opposed to attempting field goals; at one point southern was documented to have made just three successful kicks in the decade prior to a november 1955 game—and perhaps even extending for an undocumented period of time after that as well. a contemporary newspaper article concerning a banquet to be held to recognize mumford for his then-twenty years of service to southern summed up his career: