The 20-year-old arrives in the West having spent the last two seasons with Western Sydney Wanderers, for whom she made a total of eight W-League appearances.
Regarded as one of the most promising young 'keepers in the country, Newbon twice claimed the W-League Save of the Week Award last term and is now targeting further success with Glory.
"It’s a new challenge for myself," she said.
"I want to work hard for the club and hopefully help them build another Premiership-winning team.
"Alex Epakis [Head Coach] is very much in the mindset of getting the club back up towards the top of the table not just next season, but in the years to come as well.
"So I’m very excited to be joining Glory and can’t wait to get started."
Epakis, meanwhile, is relishing the prospect of linking up with the shot-stopper once again having previously worked with her during his time at Sydney University.
"We are happy to have Court at Perth Glory for next season," he said.
"She is joining us after spending two seasons at Western Sydney where she was able to showcase her ability and potential.
"Her shot-stopping and distribution skills are very strong and she is a focused and committed character.
"Despite her age, Courtney has experienced strong levels of success at various levels of the game and is a fantastic addition to our ‘keeper options.
"I look forward to seeing her progress and develop while working very hard to compete and add value to the squad."
Glory CEO Tony Pignata is similarly pleased that yet another young, hungry and talented player has joined the club’s ranks for 2021/22.
"Alex is determined to have strong competition for places across the board next season and Courtney will certainly help provide that in goal," he said.
"She is another excellent addition to a squad which is shaping up extremely well."