After serving in the army in World War II, he moved with his family to a soldier's block in western Victoria near Camperdown, where he raised his three sons, all of whom went on to compete alongside their father in the Olympics.

Roycroft rode throughout his childhood, racing his horses over tree branches with his friend Lawrence Morgan, later an Olympic equestrian competitor.

[2] At about the age of fourteen he left school and moved with his mother and father's brother to New South Wales, where he was a messenger for the Water Commission in Leeton and later a sharecropper.

After the war, they moved with their son Barry (born 1944) to a 200-hectare (500-acre) soldier's block near Camperdown in western Victoria, where they set up a dairy farm.

The eventing team needed three rider–horse combinations to finish the competition, but only had two remaining (excluding Roycroft) because one of their horses was unable to ride.

Consequently, Roycroft left his hospital bed against his doctors' advice to finish the event the next day, allowing his team to win the gold medal.

[9][10] He competed at the next four Olympics, winning bronze medals in the team events at the 1968 Mexico City and 1976 Montreal Games, alongside his son Wayne.