Mamby was born in South Bronx, New York, to Victoria, of Spanish descent, and father, Robert, from Jamaica.
[3] He held the WBC super lightweight title once, starting his 2+1⁄2-year reign in February 1980 by going to South Korea to stop titlist Kim Sang-Hyun in the 14th round.
He was to fight WBA champion Aaron Pryor in the summer of 1982 for a unification bout in the super lightweight division, but instead fought and lost his WBC title by split decision to Leroy Haley in June of that year.
At the age of 60, Mamby announced a comeback which was to have taken place in Lapwai, Idaho at the Pi-Nee-Waus Community Center of the Nez Perce Tribe,[4] in a card that was subsequently canceled.
[5] Mamby fought several weeks later, weighing 1491⁄2 pounds (67 kilograms) and lost a ten-round decision to journeyman fighter Anthony Osbourne in the Cayman Islands.