[2][3][4] He started to play football in 1963 at the junior teams of Metalul Târgoviște working with coaches Eugen Popescu and Gheorghe Ticușan, making his debut for the senior team on 17 March 1965 in a 1–0 victory, in which he gave the assist of the goal against UTA Arad in the 1964–65 Cupa României, after being noticed by Rudolf Wetzer who was the counselor of head coach Gheorghe Nuțescu.

[7][9][10] He remained at Dinamo throughout his career, winning six Divizia A titles, a competition in which he made 454 appearances (only in one of them coming to the field as a substitute) and scored 53 goals, also winning two Cupa României and playing 33 games in which he scored 3 goals in European competitions, including appearing in both legs of the 4–3 victory on aggregate against his childhood favorite team, Inter Milan in the 1981–82 UEFA Cup.

[3][7][9][11][12][13][14] His last game played was a Divizia A match which took place on 18 June 1983 against Universitatea Craiova which ended 1–1, being replaced by coach Nicolae Dumitru in the 25th minute with Nelu Stănescu as he suffered an injury.

[4][10][15][16] Dinu won three times (1970, 1972, 1974) the Romanian Footballer of the Year award, also in 1970 along with Dinamo teammate Florea Dumitrache he was nominated for the Ballon d'Or.

[22][23][24] He played three games at the successful 1970 World Cup qualifiers, also being used by coach Angelo Niculescu in all the minutes of the three group matches from the final tournament as Romania did not advance to the next stage.

[2][3][10][4][31] He also coached CS Târgoviște, ASA Târgu Mureș, Universitatea Cluj and Olt Scornicești, having a total of 218 matches as a manager in the Romanian top-division, Divizia A consisting of 118 victories, 35 draws and 65 losses.

[3][4] Cornel Dinu wrote sports columns in the magazine "Flacăra" and the daily "Scânteia tineretului" during Romania's communist era, and after 1989 in the newspapers "Sportul", "Gazeta Sporturilor", "Dimineața", "Gândul", "Național", "Adevărul", "Cultura" and "Fanatik".