Career
He played for the South Dragons in the Australian National Basketball League (NBL). Shanahan was considered one of the best 3 point shooters in the NBL but has been criticised for his infrequent shooting. At 6 foot 5 inches tall, Shanahan was a versatile player who can play most positions on the floor.
He led the NBL in three point percentage in 1999.
Shanahan attended at the Australian Institute of Sport in 1993. He débuted in the NBL in 1992, and has since played for nine teams in his career in the league and for the Kilsyth Cobras in the SEABL. He has played for the following teams:
1992-1993: South East Melbourne Magic (NBL Championship, 1992)
1994-1998: North Melbourne Giants (NBL Championship, 1994)
1998/99: Brisbane Bullets
1999/2000: Cairns Taipans
2000-2002: Wollongong Hawks (NBL Championship, 2001)
2002/03: Canberra Cannons
2003/04: Hunter Pirates
2004-2006: Perth Wildcats
2006—2008: South Dragons
2009—20012: Coffs Harbour Suns
Mathematics
2013–present Section 8 Superleague (Scoresby Scorpions)
Currently, Shanahan is the Operations and Development Manager for the Coffs Harbour Suns.
He is also the head coach of the SEABL Mens Knox Raiders.