Doroftei took up boxing at the age of 14 at the Ploieşti boxing club. From 1983 to 1984, he won every Romanian national junior title. He went on to win four national senior titles in 1992–1994 and 1997. He won bronze medals at the 1992 Summer Olympics in Barcelona and the 1996 Summer Olympics in Atlanta. In addition, he was declared World Champion in 1995 and European Champion in 1996. His record as an amateur was 239 victories and 15 defeats.