Harrie Smolders started riding at the age of eight but did not yet have a particular passion for show jumping at that time. He won dressage and eventing competitions early in his career.
At the age of 16, he decided to devote himself to the CSO, abandoning football, which he also played. At the age of 18, he joined Johan Heins.
Horseback riding is a family affair because his sister was also a rider, as were his grandfather and father, who rode and raised horses.
In 2002, he joined the EuroHorse stables of Axel Verlooy in Belgium. He trains and markets horses and coaches the riders in the stables.
In 2017, he was named Rider of the Year in the Netherlands.