Ionel Augustin, nicknamed Oneață was born on 11 October 1955 in Bucharest and started to play football in 1966 at junior level at Dinamo București, making his Divizia A debut for the senior squad on 23 April 1975 in a 5–0 victory against Chimia Râmnicu Vâlcea, winning the title in his first season spent at the club, coach Nicolae Dumitru giving him a total of five appearances.

[2][5] Afterwards, Augustin returned to Dinamo where for several years he would form a successful offensive trio with Gheorghe Mulțescu and Costel Orac, together being called "AMO" by the fans, a nickname inspired by their initials from the first letters of their family name.

[2][4] He also won three Cupa României but played in only one of the finals, the one from 1984 when coach Dumitru used him the whole match in the 2–1 win over rivals Steaua București.

[8] He made some notable performances with The Red Dogs in European competitions, as helping the club eliminate Inter Milan by scoring one goal in the 4–3 victory on aggregate from the 1981–82 UEFA Cup, also appearing in seven matches in the 1983–84 European Cup campaign, scoring one goal against Kuusysi Lahti, one in a 3–0 victory from the first leg that helped them eliminate title holders, Hamburg and one against Dinamo Minsk, reaching the semi-finals where the campaign ended in front of Liverpool.

[2] Ionel Augustin played 34 matches and scored three goals for Romania, making his debut on 13 December 1978 under coach Ștefan Kovacs in a friendly which ended with a 2–1 loss in front of Greece.