Luke McLuke's sire was Ultimus, and his dam was an imported mare named Midge, a daughter of the English Thoroughbred
Trenton. Midge's dam was another imported mare named Sandfly by the English stallion
Isonomy. Ultimus was
inbred to
Commando, as both his sire and dam were sired by
Domino. Ultimus never raced, however. at
Castleton Stud, but was sold, along with the entire stock of the 1911 foal crop, in 1912 as
yearlings. He was initially bought as part of a group lot of all 16 of the
colts, purchased by William A. Prime for $25,000 (), Although unraced as a two-year-old, Luke McLuke raced as a three-year-old for Schorr. In Schorr's ownership, the stallion won the Belmont Stakes. Luke McLuke was expected to be a sprinter, as his breeding, especially on his sire's side, mainly was raced at shorter distances. ==Racing career==