His ability attracted the attention of other cyclists and Harris joined the Bury section of the Cyclists' Touring Club and then its racing offshoot, the Lancashire Road Club.
In 1935, he won his first race, a half-mile handicap event held on a grass track in Bury, and also started competing in individual time trials.

Harris moved from the motor mechanics job to a slipper factory, then, in early 1936, to a paper mill which he felt would pay him enough in the winter to spend the summer training and competing.
During 1936, he raced on grass tracks in Lincolnshire, then competed in and won his first events in conventional competition at Fallowfield Stadium in Fallowfield, Manchester.

In early 1937, he was confident he could support himself as an athlete, selling the prizes he won as an amateur, and left the paper mill to focus on the summer cycle racing season, returning to the mill the following winter (repeating the process the following year).
He continued to win races and attract attention, and by the summer of 1938 was able to beat the existing British sprint champion.
At the end of that season, he joined Manchester Wheelers' Club, and in 1939 won a major race in Coventry, leading to his selection for the world championship in Milan, Italy.
He travelled to Milan and had familiarised himself with the Velodromo Vigorelli when World War II broke out and the British team was recalled to the UK.

Harris joined the 10th Hussars in the North Africa Campaign as a tank driver but was wounded, transferred to the Royal Army Service Corps, and later invalided out of the services as medically unfit in 1943.
He liked to joke that he was one of the few men to leave the army less fit than when he joined.
Despite the judgment of the army medics, in 1944, he won the 1,000 yards (910 m), quarter-mile and five-mile (8 km) national cycling championships.
He retained the two shorter titles in 1945 and added the half-mile on grass.
He was invited to race in Paris in 1945 and again impressed the crowds, and he was expected to do well in the 1946 world championships in Zurich, Switzerland, only to have his chances ruined by an over-enthusiastic pre-race massage.
Harris's amateur world championship achievements were celebrated in 1947 when Cycling Weekly awarded him his own page in the Golden Book of Cycling.

By the time Harris won the world amateur sprint title in Paris in 1947, he was already employed and equipped by bicycle manufacturer Claud Butler and was testing the boundaries of amateurism.
The cycling world expected that Harris would take three titles in the 1948 Summer Olympics: the sprint, the tandem sprint and the kilometre time trial, but three months before the London Games, he broke two ribs in a road accident.
After hospital, with a few weeks remaining to the games, training, competing and winning, he fell in a ten-mile (16 km) race at Fallowfield and fractured an elbow.
Completing the rest of his preparation in a plaster cast, he had to be satisfied with two silvers, being beaten by Italy's Mario Ghella in the final of the sprint, and partnering Alan Bannister to second place in the tandem sprint (timetable constraints meant Harris's place in the kilometre was taken by another rider, Tommy Godwin, who won a bronze medal).
Two weeks later, he claimed a bronze medal in the 1948 world championships sprint in Amsterdam.
He was named sportsman of the year by a poll in 1949, winning by 7,000 votes over the football player, Billy Liddell.
His ability attracted the attention of other cyclists and Harris joined the Bury section of the Cyclists' Touring Club and then its racing offshoot, the Lancashire Road Club. In 1935, he won his first race, a half-mile handicap event held on a grass track in Bury, and also started competing in individual time trials.
Harris moved from the motor mechanics job to a slipper factory, then, in early 1936, to a paper mill which he felt would pay him enough in the winter to spend the summer training and competing. During 1936, he raced on grass tracks in Lincolnshire, then competed in and won his first events in conventional competition at Fallowfield Stadium in Fallowfield, Manchester.
In early 1937, he was confident he could support himself as an athlete, selling the prizes he won as an amateur, and left the paper mill to focus on the summer cycle racing season, returning to the mill the following winter (repeating the process the following year). He continued to win races and attract attention, and by the summer of 1938 was able to beat the existing British sprint champion. At the end of that season, he joined Manchester Wheelers' Club, and in 1939 won a major race in Coventry, leading to his selection for the world championship in Milan, Italy. He travelled to Milan and had familiarised himself with the Velodromo Vigorelli when World War II broke out and the British team was recalled to the UK.
Harris joined the 10th Hussars in the North Africa Campaign as a tank driver but was wounded, transferred to the Royal Army Service Corps, and later invalided out of the services as medically unfit in 1943. He liked to joke that he was one of the few men to leave the army less fit than when he joined. Despite the judgment of the army medics, in 1944, he won the 1,000 yards (910 m), quarter-mile and five-mile (8 km) national cycling championships. He retained the two shorter titles in 1945 and added the half-mile on grass. He was invited to race in Paris in 1945 and again impressed the crowds, and he was expected to do well in the 1946 world championships in Zurich, Switzerland, only to have his chances ruined by an over-enthusiastic pre-race massage. Harris's amateur world championship achievements were celebrated in 1947 when Cycling Weekly awarded him his own page in the Golden Book of Cycling.
By the time Harris won the world amateur sprint title in Paris in 1947, he was already employed and equipped by bicycle manufacturer Claud Butler and was testing the boundaries of amateurism. The cycling world expected that Harris would take three titles in the 1948 Summer Olympics: the sprint, the tandem sprint and the kilometre time trial, but three months before the London Games, he broke two ribs in a road accident. After hospital, with a few weeks remaining to the games, training, competing and winning, he fell in a ten-mile (16 km) race at Fallowfield and fractured an elbow. Completing the rest of his preparation in a plaster cast, he had to be satisfied with two silvers, being beaten by Italy's Mario Ghella in the final of the sprint, and partnering Alan Bannister to second place in the tandem sprint (timetable constraints meant Harris's place in the kilometre was taken by another rider, Tommy Godwin, who won a bronze medal). Two weeks later, he claimed a bronze medal in the 1948 world championships sprint in Amsterdam. He was named sportsman of the year by a poll in 1949, winning by 7,000 votes over the football player, Billy Liddell.
Reg Harris