During World War I, Beresford was wounded in France in 1918. He then returned to London and joined his father's furniture manufacturing business. As a member of the Thames Rowing Club, Beresford won the Diamond Sculls at Henley four times in the 1920s. He also twice won in the Grand and the Goblet and once in the Stewards' in his career at Henley.

At the 1920 Olympic Games in Antwerp, Belgium, Beresford finished a close second to American John Kelly in the single sculls. He returned to the Olympics in 1924 in Paris, where he won the gold medal in single sculls. At the 1928 Olympic Games in Amsterdam he captured the silver in the coxed eights, and he earned a gold medal in the uncoxed fours at the 1932 Games in Los Angeles. Beresford's tactical knowledge allowed him to remain competitive well past his peak years. At the age of 37, he paired with Leslie Southwood to win the gold medal in the double sculls at the 1936 Berlin Olympics. Their Olympic success inspired Henley Regatta to add a double sculls competition in 1939, and Beresford and Southwood won the inaugural race. Beresford was active in coaching and amateur athletics administration and was appointed a commander of the British Empire in 1960.