Gibson attended Omaha Technical High School, where he participated on the track, basketball, and baseball teams. Health issues resurfaced for Gibson, though, and he needed a doctor's permission to compete in high school sports because of a heart murmur that occurred in tandem with a rapid growth spurt. Gibson was named to the All-State basketball team during his senior year of high school by a newspaper in Lincoln, Nebraska, and soon after won a full athletic scholarship for basketball from Creighton University. Indiana University had rejected him after stating their Negro athlete quota had already been filled.