The 2010 series champion joined the Ford squad in bizarre circumstances earlier this year, replacing a luckless Will Davison, whose funding ran dry due to the pandemic.
By that stage Courtney had already been through a dramatic split with Team Sydney after just a single round, and was eyeing a limited wildcard programme only for Davison's departure to facilitate a surprise full-time return.
He's since settled in nicely at Tickford, scoring a podium and four top four finishes.
That relationship is now set to continue for at least another year, Courtney and Boost Mobile signing on with the team for 2021.
“This year’s been an absolute roller coaster with all that’s gone on, but to end up here at Tickford thanks to Boost Mobile has been amazing, and to continue this relationship into 2021 is just fantastic,” Courtney said.
“I’ve developed great relationships with the boys on my car, the team has been super welcoming since Day 1, and fortunately we’ve been able to score some strong results on track, too.
"I really couldn’t have asked for a better place to be, and the partnership has been great for Boost as well. I guess the saying goes ‘if it ain’t broke, don’t fix it,’ so it makes sense for all of us to keep the party going.”
Tickford boss Tim Edwards added: “When you look at the way this all came together, it’s quite impressive what James and the Boost Mobile crew have been able to accomplish.
“In reality, he still hasn’t had a single test day with us, but has fit right in with the team and the car extremely well. With a proper chance to prepare for a full season, we’re both confident there will be much more to come from JC and the Boost Mobile Mustang in 2021.
"To continue on with Boost in itself is tremendous, obviously they jumped on board at a critical time for our team, and it’s paid dividends for everyone. Our partnership is going from strength to strength, and points to more successes on and off the track in 2021.”
Courtney is teamed up with teenage sensation Broc Feeney for this weekend's Bathurst 1000.