John and William became co-proprietors of the Club Stables in Kelper Street, Warrnambool, in 1890, where they conducted a business of hired horse drawn vehicles of various types as required by the public.
Prior to this time they were well known on the horse racing scene. They raced a number of horses in partnership with John taking over the role as trainer and rider. He was regarded as one of the most fearless cross country horsemen of his time, and on many occasions he would appear at Gymkhanas as a Rough Rider. On the track he rode many winners, particularly thoughout the Western District of Victoria and South Australia. The Junior Steepleshase run at Warrnambool's Annual Winter Meeting brought John McCullough victory on two occasions, he rode "Feathernaught" in 1883 and "Ranger" in 1887.
In the 1883 race "Feathernaught" fell at the fence, a horse called "War Dance" passed the fallen McCullough and Feathernaught's chances of winning appeared zero, but McCullough remounted and gave chase and managed to get home a narrow but thrilling winner.
Choosing a favourite from his own horses he selected his sweet tempered mare "Semaphore", she didn't reach the heights of others in the team but with John McCullough in the saddle "Semaphore" managed to finish third in the Warrnambool Grand Annual Steeplechase in 1887, and won the South Eastern Steeplechase at Mt.Gambier the following month.
Mr. R. Hustler from Penhurst District owned the Paris-Micha gelding-"Tasman", apparently this horse showed tons of ability but would sherk the task ahead of him. A deal transpired between Mr. Hustler and John and William McCullough and for the sum of Twenty Pounds the Brothers became the owners of "Tasman". John worked wonders with "Tasman" and with the Warrnambool Grand Annual Steeplechase as his target he took him to Camperdown where he won the Two Mile Steeplechase in the Grand Annual of 1902. And as recorded above won the Warrnambool Grand Annual Steeple Chase in the same year on "Tasman". [See "McCullough Photo Album 1" page for an additional photo of John and "Tasman"]