Migliore, 46, told those who gathered for the announcement at Belmont Park it was "no big surprise why we're here."
"My career as a jockey is over," he said. "It's not by choice: I was in the doctor's office on Wednesday of last week and he assured me that I would never ride another thoroughbred again. He works on many NFL players and said if you have a level two fusion, you have to retire. I have a level four fusion."
Migliore was thrown during a Jan. 24 race at Aqueduct, just the latest of many injuries he suffered during his 30-year career.
His 4,450 victories came in 30,102 races and produced more than $160 million in winnings.
He won the 1981 Eclipse Award as champion apprentice jockey and won the 2008 Breeders' Cup Turf Sprint aboard Desert Code. He also won the Eddie Arcaro Award as Outstanding Jockey in 1981 and 1985, the 2003 Mike Venezia Memorial Award for extraordinary sportsmanship and citizenship, and the 2008 George Woolf Memorial Jockey Award.
"Horses have given me everything in life, everything good in my life stems from horses," Migliore said.