Born in Canada, Vella has dual nationality, Maltese and Canadian. His family moved to Malta in 1970. He started playing football with Rabat Ajax and when he was promoted to the senior team, he soon became an invaluable asset, rarely missing a game.
Silvio Vella was chosen as Malta's Footballer of the Year in the 1993-94 season, in spite of Rabat Ajax' relegation as the first (and to date only) player from a relegated team to win that award. This was at the height of his career, and to keep on playing in the Premier Division he joined Hibernians. Although it was initially a loan deal, it became a permanent transfer later on, and he remained a Hibernians player for the rest of his career.
After his retirement in the summer of 2002, he joined the Malta Football Association's coaching staff for the various national teams. He served as assistant coach for the U21 national team until October 2009, when he became U19 national team coach. In June 2010 Vella joined his former club Rabat Ajax as their new Manager.