Da Big Hoss won three of his first seven races but really broke through in the summer of 2015 at Saratoga Race Course, where he won an allowance race and the prevailed in the John's Call Stakes to earn his first career stakes victory. He followed with his first graded stakes win in the Grade 3 Kentucky Jockey Club Stakes at Kentucky Downs.
Da Big Hoss was sent to the Breeders' Cup World Championships after his graded stakes victory and finished sixth in the Longines Breeders' Cup Turf before closing out his 4-year-old season with a third-place finish in the Grade 3 W. L. McKnight Handicap at Gulfstream Park.
Da Big Hoss opened his 2016 season with another graded stakes win in the Grade 3 John B. Connally Turf Cup Stakes at Sam Houston Race Park. After an unplaced finish in the Grade 2 Mac Diarmida Stakes, Da Big Hoss put together a nice winning streak. He won the Grade 2 Elkhorn Stakes at Keeneland Race Course before winning the $300,000 Belmont Gold Cup Invitational Stakes. He then shipped to Arlington Park, where he was a dominant winner of the American St. Leger Stakes on the International Festival of Racing card. Da Big Hoss extended his winning streak to four with a victory at Kentucky Downs in the Grade 3 Calumet Farm Kentucky Turf Cup Stakes.