Born in Ploieşti, Romania, Doroftei began boxing at the age of 14 at the Prahova Ploieşti boxing club. From 1986 to 1988 he won every Romanian national junior title. He went on to win five national senior titles in 1992, 1993, 1994, 1996, and 1997. He won bronze medals at the 1992 Summer Olympics in Barcelona and the 1996 Summer Olympics in Atlanta, Georgia. In addition, he was declared World Champion in 1995 and European Champion in 1996 and 1997. His record as an amateur was 239 victories and 15 defeats.
In 1997 Doroftei became a professional boxer, signing with the Canadian club Interbox. On January 5, 2002 he won the WBA world lightweight title, winning in a split decision over Argentinian boxer Raul Horacio Balbi 112-115, 114-113, 115-112. On May 31, the two fought again in Bucharest; this second fight was an unanimous decision for Doroftei, 118-111, 117-112 and 118-110.
A lightweight title unification bout May 17, 2003 with American boxer Paul Spadafora, the IBF champion, ended in a draw, 114-114, 115-113, 114-115.
On October 24, 2003, Doroftei was to fight a match against Panamanian boxer Miguel Callist. Doroftei had already announced that this would be his last professional match regardless of the result. As it turned out, the match was cancelled after the Doroftei exceeded the maximum weight for lightweights at the weigh-in: he was 1.915 kg over the 61.235kg (135lb) weight limit, so he lost his WBA title.