Marzolini's first steps as footballer were in Deportivo Italiano, soon moving to the young divisions of Ferro Carril Oeste in 1955. After a discussion with the club managers asking for playing in the Senior team, Marzolini was suspended for two years. Nevertheless he debuted in Primera División in May 1959, playing against Boca Juniors, that would hire him the following year.
Marzolini debuted with Boca on April 3, 1960 against Estudiantes de La Plata, defeating it by 2-1. Boca finished 3rd. at the end of the season, with Marzolini playing of the games.
In 1961 Marzolini scored his first goal in the top division, but Boca did not a great campaign, finishing 5th. Marzolini played a total of 29 games scoring 2 goals. The first achievement came in 1962 when Boca won the title, with notable players such as goalkeeper Antonio Roma, Brazilian striker Paulo Valentim and Peruvian Norberto Menéndez. Boca finished 1st with 42 points. Marzolini was also the most caped player of the season with 28 games played.