Dumitriu was born on 5 November 1942 in
Bucharest, Romania and began playing junior-level football in 1957 at
Locomotiva București, then joined Progresul CPCS București. He made his
Divizia A debut on 25 March 1962, playing for
Jiul Petroșani under coach
Bazil Marian in a 3–2 victory against
UTA Arad. In the following season he played in the first half for
Viitorul București, going for the second half to
Rapid București. He made four appearances in European competitions for Rapid (including one in the
Inter-cities Fairs Cup), most notably helping
The Railwaymen eliminate
Trakia Plovdiv in the
1967–68 European Cup and advance to the following round where they were eliminated by
Juventus. He also won two
Balkans Cups, netting a brace in the 2–0 win in the second leg against
Farul Constanța in the final of the
1964–66 edition. He suffered a lung illness which kept him off the field for one and a half years and in 1968, Stănescu took him to
Steagul Roșu Brașov, aiming to help him relaunch his career. Afterwards he returned for two seasons to Rapid where he made his last Divizia A appearance on 10 March 1974 in a 2–0 away loss to
Argeș Pitești, totaling 235 matches with 68 goals in the competition. Dumitriu ended his career by playing three seasons in
Divizia B, the first one at
Chimia Râmnicu Vâlcea and the other two at
Progresul București, helping both teams earn promotion to Divizia A. ==International career==