Hamish’s musical journey began when he took up the guitar at the age of eight. By the time he turned eleven he had switched to drums and bought his first set of drums with money saved up from a paper round in his Sydney neighbourhood. Rosser's first gig was with high school punk band called "The Warthogs" who covered The Clash, The Ramones and the Sex Pistols.
Rosser has launched a beer called Skinny Blonde. The beer won the Peoples Choice awards at the 2008 Australian Beer Festival held at the Rocks in Sydney.
In June 2009, Skinny Blonde attracted national controversy across Australia over its beer bottle packaging which, through the use of modern ink technology, has a 1950s style pin up girl called 'Daisy' on the beer bottle label, slowly revealing herself as the beer level drops and the bottle temperature rises. This angered feminists who claimed the beer was "another blatant example of the alcohol industry objectifying women to move product". In response, Rosser stated,
This generation of Aussies have grown up on the beach and topless girls in bikinis are commonplace. The label and website is in no way meant to offend women or anyone else, rather embrace the Australian beach culture.
He was also quoted as saying that the beer was a "bit of cheeky fun".