He grew up in the south-west Sydney suburb of Picnic Point, with his father, mother and two brothers.

The Western Bulldogs were perceived to have taken a bit of a gamble in using such a high draft selection on a young player from the suburbs of Sydney, which traditionally is not an Australian football area.

Addison was one of the better NSW-ACT Rams players in the 2005 AFL Under-18 Championships, coming via the St George Crows in the SFL.

Addison started his career by playing as a medium forward, or on the ball, under the tutelage of head coach Rodney Eade.

Although his career between 2006–2011 was positively noted for his hard-attack on the football, he was subject to criticism regarding his disposal efficiency, a facet of his game play that saw him in-and-out of the Western Bulldogs team across those 6 years.