MOUNT AIRY — Gregg McCarron, who won over 2,400 races in a 24-year riding career and who steered his younger brother Chris to a Hall of Fame career as a jockey, has died. He was 77.

McCarron died Thursday after a heart attack at his farm in Mount Airy, the New York Racing Association said Saturday after being informed by his brother.

Gregg McCarron began his riding career at Suffolk Downs in Boston in 1969 and rode in 20,595 races before retiring in Maryland in 1993. He was the leading apprentice rider at Rockingham Park in New Hampshire in his first year.

He was aboard multiple Grade 1 stakes winners, including On the Sly (1977 Jockey Club Gold Cup) and Bounding Basque (1983 Wood Memorial) and Broom Dance (1982 Alabama Stakes).

He rode mainly in New England, New York and Maryland, and he trained horses for a short while on the Maryland circuit after his riding career ended. McCarron became a racing commentator for NBC Sports, covering the Breeders’ Cup world championships.

“Gregg led me to my career as a jockey, and he was there for me every step of the way,” Chris McCarron said. “He was my idol, and I always tried to emulate everything he did. He mentored me in my formative years, and I would not have had the career I did without him in my life.”

Gregg McCarron is survived by his wife, Darlene, and son, Matt, who was a two-time champion steeplechase jockey.