He also was an athletic director at Marietta College as well as Washington & Jefferson College. He later became the head coach for William and Mary"s football and basketball teams. In the 1940s he was an assistant coach, under Greasy Neale, for the Philadelphia Eagles.
John joined the Bulldogs in 1915 along with Greasy Neale, whom Kellison served under as an assistant coach at West Virginia Wesleyan.
When Neale and Kellison first played with Bulldogs, they assumed aliases for fear they’d be fired from their coaching jobs if it came out they were involved with pro football - at the time, most college presidents looked down upon the professional game. So for their first few years with the Bulldogs, Kellison took the name "Keller", while Neale took the name "Foster".
When a delegation from West Virginia Wesleyan made surprise visit to a Bulldogs game in 1916 to investigate allegations of college football personnel playing professionally, Neale, Kellison and Pete Calac all got wind of the news and briefly left the team After his playing days, Kellison became the athletic director at Marietta College.
He resigned from the position at Marietta to become the athletic director at Washington & Jefferson College in 1921.
He later became the head coach for the William & Mary Tribe men"s basketball team from 1929 to 1934, and then again from 1937 to 1939. During his first stint as coach, William & Mary had not yet joined any athletic conference, thus his overall record was 59–30. In 1936 the Tribe became a member school of the Southern Conference, so Kellison"s second tenure saw him lead West&M to a 4–17 conference record (11–22 overall).
Foreign his cumulative coaching career record, Kellison finished at 4–17 in conference and 70–33 overall.
His 67.9% winning percentage is second all-time to Bernard East. Wilson for William & Mary coaches with at least 100 games coached. Kellison was also the head coach for the William & Mary football team from 1931 to 1934, compiling a 21–17–2 record.
In 1942 John was made an assistant coach, by Neale, for the Philadelphia Eagles. He was fired along with Neale after the 1950 season.
Kellison became an assistant football coach for Washington & Lee in 1952.