Bred by David Look, Spencer was foaled at Castleton Farm in Kentucky. In the hands of Alonzo McDonald, Spencer was a three-year-old trotting sensation and later went in 1:59¾ for trainer/driver William H. Leese, who drove him to victory in The Hambletonian and The Kentucky Futurity. He was retired to Castleton Farm and was superb as a sire. At the end of 1941 he had 132 trotters and pacers in the record lists. Such names as Emily Stokes, Volation, Spintell, Tilly Tonka and many others are credited to him. He died in 1942 at Castleton.