[3][4][5][6] He started playing football for the junior squads of Giulești based club, Rapid București, this being the team for which he would play all of his career, making his Divizia A debut under coach Valentin Stănescu on 31 March 1966 in a 1–0 away loss against Petrolul Ploiești and in the next season he won the competition, Stănescu using him in only eight games in which he scored one goal, as the first options for the offence were Ion Ionescu and Emil Dumitriu.
[3][5][6][7][8][10] He took part in Rapid's 1971–72 UEFA Cup campaign, playing all six games, as the team reached the eight-finals, eliminating Napoli and Legia Warsaw against whom he scored a double, being eliminated by the team who would eventually win the competition, Tottenham, also taking part in the 1972–73 European Cup Winners' Cup campaign, playing all six games, helping the team reach the quarter-finals, eliminating Landskrona BoIS and Rapid Wien against whom he scored a goal, being eliminated by Leeds United who reached the final.
[5][6] Alexandru Neagu played 15 games and scored four goals for Romania, all under the guidance of Angelo Niculescu, making his debut on 9 February 1970 in a friendly which ended 1–1 against Peru.
[2][3][4][5][8] He played six matches at the 1972 Euro qualifiers, managing to reach the quarter-finals where he scored two goals but Romania was defeated by Hungary, who advanced to the final tournament.
[2] Neagu's last game played for the national team took place on 20 September 1972 at the 1974 World Cup qualifiers in a 1–1 with Finland.