It's the second influential Matildas player that the Gunners have signed, with Caitlin Foord also making the move to Meadow Park in the winter transfer window.
On the international stage, the attacking-minded full-back is the vice-captain of the Australian national team, the Matildas, and has featured 82 times since making her debut at age 18.
She joins Arsenal having picked up a wealth of silverware in her career so far, the W-League Championship five times and W-League premiership twice in addition to being named W-League Young Player of the Year and FFA Under 20 Footballer of the Year twice.
'So excited that it's finally done'
Speaking in an interview with Arsenal.com when the deal was announced, Catley spoke of her excitement to be able to play for the Gunners:
“This is something that I’ve been looking forward to for a long time,” said Catley, “Arsenal is a place where I’ve imagined myself playing for a long time too.
“I’m so excited that it’s finally done. This will be my first taste of European football and obviously there’s so much to look forward to and so many big occasions to come. I can’t wait to get started.”
'We're excited to have her'
Speaking in the same article on the Arsenal website, fellow Australian and Gunners Head Coach Joe Montemurro spoke about how they are 'privileged' to have Catley at the club:
“We’re privileged to have Steph at the club
“She suits our fluidity and she’s very good in a positional sense, but more importantly she’s very effective going forwards, so we’re excited to have her as part of the squad and we’re looking forward to some exciting times together!”