After six seasons with Calvisano he moved to Amatori Milano, then owned by Silvio Berlusconi and known as "Milan Rugby", and won an Italian title in 1995; got back to Calvisano he joined the Italian Championship's Final 6 times in a row, from 2001 to 2006, winning the title again in 2005.
Vaccari won his first cap in 1991 against Namibia in Windhoek (defeat 7–17, although he scored a try at his debut); he went on playing three consecutive editions of the Rugby World Cup (1991, 1995 and 1999).
Vaccari was part of the Italian team that won for the first time the 1997 FIRA Trophy against France.
Vaccari was also invited by the Barbarians to play a match in Leicester in April 1998, which he considers as "a highlight in his career".
In 2003 Vaccari graduated in Architecture at the Politecnico, University of Milan, together with his fellow National teammate Massimo Giovanelli.