Hayes, Seamus (1924–89), showjumper, was born 5 November 1924 in Cork, son of Maj.-gen. Liam Hayes and Kathleen Hayes (née Walsh). The family moved to Dublin in 1930 when his father became commanding officer of the equestrian school in McKee Barracks, Dublin; he later became adjutant general of the army. From childhood he had a keen interest in horses. In 1932 he got his first pony, and on only his fourth outing he won his class and received the first of many red rosettes. He was educated at Castleknock College.
1939 was to witness the beginning of his successful career when his father bought him a pony, Snowstorm. They first began to win pony classes at local Dublin shows, and in 1943 they won the pony championship in the spring show in the RDS. Snowstorm was sold on two occasions but failed to win anything. However, in 1948 the two were reunited when Tommy Makin bought the horse and asked Seamus to ride for him. It was clear that he could get the best out of any horse, as they went on to twenty-five straight wins. He remained in Yorkshire for five years and won every major championship in Britain. In 1949, 1950, and 1952 he won the leading showjumper of the year award at the Horse of the Year Show, and from 1950 to 1952 he was the Irish National Champion Show Jump rider. He quickly rose to prominence and had great success with the mare Sheila, the only horse to win two BSJA championships. He later established his own stables in Northamptonshire but his career was badly disrupted when he broke his pelvis in a riding accident.
In 1957 he returned to Ireland and gave up his competitive career while he took a position as an instructor in McKee Barracks. Less than two years passed, though, before he returned to the show ring, riding for the Dublin-based horse-owner Omar van Landegham. Within three months he won the Dublin Grand Prix, but complaints followed because some maintained he was a professional. By 1960, though, he was accepted as an amateur but was disallowed from taking part in the Olympics. In that same year he was unbeatable and represented Ireland in the first civilian show-jumping team alongside Brian McNicholl, Leslie Fitzpatrick, and John Brooke, who went on to win the world championship in Venice. In 1961 and 1963 he won the Daily Mail Cup, and won the British Show Jumping Derby at Hickstead in its inaugural year in 1961 and 1964. It was with his horse Goodbye, from the McGrath stables in Sandyford, Dublin, that he had most success, clearing 7 ft 2 in. (2.18 m) on six occasions. He was a member of two Irish teams that won the Aga Khan Cup in Dublin (1963, 1967).
After a bad fall at the RDS spring show in 1973 he decided to retire. He was a proud and courageous competitor, a perfectionist in every way. He had a great love for the sport, and as a result some believe that he was taken advantage of, as he never earned as much money as other riders in his class. He died in Naas, Co. Kildare, on 30 October 1989.
He married (1964) Mary Rose Robinson, who was also a showjumper and from a notable equestrian family; they had a son and a daughter. During his retirement the couple trained many horses at Greenside on the Curragh.