Recruited from Labrador, Queensland, Osborne debuted for Hawthorn Football Club in 2001 after being elevated from the rookie list. While only playing three games in his first two seasons, since 2003 Osborne has been a regular selection when not injured. A versatile player Osborne can play as a small defender, midfielder or forward. Straight-ahead type with an aggressive streak and ability to fly for a big mark and kick spectacular goals. In 2005 he was awarded the club's 'defensive pursuits player of the year'. In 2008 Osborne played in 20 of the 22 home-and-away games, and was part of Hawthorn's premiership team.
Osborne suffered a season-ending ACL injury in Round 7 of the 2012 season. He was delisted at the end of the 2012 season, but was redrafted with pick 70 in 2012 draft. Hawthorn recruitment manager Graeme Wright said: "It's great to have 'Ossie' back on the list officially. He was very gracious in helping us from a list management point of view. We were able to get Jonathan Simpkin onto the list as a delisted free agent by delisting 'Ossie'."
He played 5 senior games in 2013, spending most of the season with Hawthorn's affiliate VFL side Box Hill. He is the only player to play in two top division Box Hill premiership sides, (2001 and 2013).
Osborne announced his retirement at Hawthorn's 2013 Best and Fairest count.
Immediately after his playing days were over, he joined Carlton as a development coach on November 27, 2013.