As a professional football player the gambling by storm Mariani, born in 1946 in Sassuolo began in the season 1965/66 at FC Modena. He subsequently played for short periods of time for Cosenza Calcio Ascoli Calcio 1914 and before he moved to Fiorentina. With Fiorentina he was in the season in 1968/69 under Bruno Pesaola Italian master, although he only came once used as a substitute.
In the 1972/73 season Mariani rescued his club Hellas Verona at the crucial direct relegation game against Sampdoria by three goals scored to make it 3-1 after initial residue. He became known abroad mainly as a striker from Inter Milan, where he supplemented well with Roberto Boninsegna. Between 1973 and 1974, he scored eight goals for Inter during one and a half years in 39 games. In the UEFA Cup 1976/77 Mariani difference with the AC Cesena in the first round against 1 FC Magdeburg 0:3 and 3:1 from where he scored the first goal for Cesena in the return game.
Overall, Giorgio Mariani scored in Serie A in 158 games 29 goals. In the B series, he hit in 29 games twice. Recently he has served his hometown club U.S. Sassuolo Calcio some time as sports director.
Giorgio Mariani died after prolonged suffering on 8 December 2011 at the age of 65 years at the Hospital of Sassuolo.