While working for the Dwyer stable, Hardy Campbell Jr. learned racehorse conditioning from future Hall of Fame trainers James G. Rowe Sr. and Frank McCabe.

The American trainer caused a sir among his English counterparts when he timed his horses' workouts, something that all race conditioners were then doing in North America and Australia.

[4] In April 1895, Campbell and Simms won the Crawford Plate at Newmarket Racecourse with a horse name Utica who was renamed in England as Eau de Gallie.

Although Hardy Campbell Jr. remained head trainer for Mike Dwyer throughout his short life, he only trained for Richard Croker until the Dwyer-Croker partnership was dissolved on May 17, 1895, in England.

[5] Back in the United States, in 1896 Campbell won the Kentucky Derby with Ben Brush and got his second American Classic win in the 1898 Preakness Stakes with Sly Fox, the latter a colt owned by Mike Dwyer's eldest son, Charles.