Guyanese-born Egerton Marcus moved to Toronto, Ontario in 1973 and soon took up boxing at the city’s Cabbagetown Youth Center. Originally a light-middleweight boxer, he moved up to middleweight at the suggestion of his coach, who had another fighter in the light-middleweight class and felt that Marcus would be better able to compete at the higher division. Marcus represented Canada at the 1986 Commonwealth Games, but was defeated by Rod Douglas of England, the upcoming gold medalist, in the second round. He was the Canadian middleweight champion in 1987, one of five such titles that he earned as an amateur, but was passed over for that year’s Pan American Games on a technicality. He was selected for the 1988 Summer Olympics, however, and, after receiving a bye in round one, he defeated Emmanuel Legaspi of the Philippines, Darko Dukić of Yugoslavia, Sven Ottke of West Germany, and Syed Hussain Shah of Pakistan to reach the finals, where he lost to Henry Maske of East Germany and settled for silver.
Marcus then turned professional and earned the NABF Light Heavyweight Title in 1992, successfully defending it three times. In a bid for the IBF World Light Heavyweight Title in 1995, he was dealt his first professional loss in 15 bouts by Maske, and then made unsuccessful attempts at the WBC Continental Americas Cruiserweight, WBO NABO Cruiserweight, and IBO Intercontinental Heavyweight Titles. In a 2001 attempt at the Canadian Heavyweight Title, he was knocked out by Razor Ruddock and retired from active competition. After running the Egerton Marcus Boxing Academy in Toronto for several years, he closed his club in 2006, changed his surname to Emba (an acronym for his club), and staged a brief comeback on the Canadian scene.