In the 2005-06 A-League season, Timpano was an essential part of Sydney FC championship-winning side - playing in 19 of the club's 24 games.
However, in the 2006-07 A-League season, Timpano made only 2 appearances (1 start) due to persistent leg injuries which continued into the start of season 2007/08. By the time Timpano recovered full fitness he found himself out of favour with the new coach only playing another 3 games for Sydney before he left the club.
In 2009, Timpano signed a two-year deal to be part of the new North Queensland Fury's inaugural A-League squad alongside current Sydney FC teammates, Robbie Middleby, Brendon Šantalab and Beau Busch. However, he once again found himself the 4th choice defensive option and remained unused throughout the season, much of which he spent on loan at Queensland League club North Queensland Razorbacks.
At the end of the season, Jacob was one of the players controversially released by the club despite being under contract. After being released, Jacob went back to New South Wales to play for Sydney United in the NSW Premier League.
During 2006, Timpano was selected and captained the Australian Under 23's national football team in their campaign for the 2008 Summer Olympics, and played in all three international matches that year against Iran, Vietnam and Uzbekistan.