The former Chelsea, Arsenal and Tottenham defender insists he is still hungry for success and hasn't come to Australia to simply wind down his career.
The former Premier League star was officially unveiled as the Glory's marquee signing on Monday and will immediately get down to work with his new club.
There is genuine excitement among Glory fans at Gallas' acquisition, and the former French international could make his first appearance for the club in Saturday's home clash with Adelaide.
But the 36-year-old has been without a club since he left Tottenham at the end of the last English Premier League season and Gallas admits he's not sure if he'll be right to face the Reds at nib Stadium.
"We will see if I can play or not," Gallas told reporters on Monday.
"I didn't play for three months so I think we have to be careful - maybe don't take a risk.
"But we will see. I am very excited tomorrow (Tuesday) to train with my new team-mates and we will see."
While he's unsure about his availability this weekend, Gallas was more forthright when it came to his goals with his new club.
Known for his passion and desire for success during his time in the EPL, the experienced defender has a sole focus for his stint in the west.
"I have a new challenge - to win a trophy with Perth Glory," Gallas said.
"I think everybody knows that I am a player who likes to win."
After an encouraging start to the new season, Glory coach Alistair Edwards couldn't hide his excitement at adding Gallas to his squad and believes it shows just how strong the A-League has become.
"It's a wonderful signing for the A-League," Edwards said.
"It shows how big the A-League has become, to attract world class players like William to the competition.
"The Western Australian community is really excited, as I am. The playing group also is, and also the coaching staff."