John"s brother Robert Eller was also an athlete, who competed for Fordham University and the Irish American Athletic Club. In 1910, Eller was considered "King of the Hurdlers." "He held the world"s record for the 220 yard, 2 foot 6 inch hurdle made at Travers Island in 1908, the time being 24 4/6 seconds and also the 220 yard 3ft. 6in. In 1912 he was eliminated in the semi-finals of the 110 metre hurdles competition.
He also participated in the pentathlon event but quit after three disciplines, with the victory going to Jim Thorpe.