The veteran will hang up his helmet as a full-timer at the end of the current campaign, just a year into his comeback with Grove Racing.
After losing his Tickford Racing seat at the end of 2020, his return to the full-time fold was initially only expected to last one season.
However Holdsworth found himself with a solid option to stay on the grid as a full-timer with the Blanchard Racing Team, which will part ways with Tim Slade at the end of 2022.
But Holdsworth ultimately declined the BRT seat, instead opting to announce his retirement so that he can concentrate on his new career in commercial real estate.
Speaking to the Castrol Motorsport News podcast, Holdsworth admitted that as of the recent Sandown SuperSprint he was still leaning towards taking the BRT ride and continuing in Supercars.
That was until the celebration for his 500th Supercars start helped him settle on the decision to call it quits.
“It was a bit of a 50/50 call to be honest," said Holdsworth.
"I hadn’t gone down very far in talks on next year but I guess before it went too far I thought I had to really assess where I was at and what I wanted for my future.
"I think that Sandown round when I hit 500 races, that was a big moment for me where I thought that’s probably enough.
"You know, 500 races is a big achievement and I thought it was probably about time that I start focusing on my career outside of motorsport and putting some time back into the family.
Another driving force behind Holdsworth's decision was his desire to fully focus on his new career.
“I think at Sandown I was still thinking that I might go again but it was after Sandown where I really had to reflect on everything and make a difficult decision," he said.
"I’ve got this part-time job at the moment, I want to go full-time with it, there’s enough work to go full-time, and it’s probably not fair to be full-time in Supercars whilst you’re not going to be 110 per cent focused on doing it properly. I think when you’re in this sport you have to be very committed.
"There’s plenty of people on the sidelines that would love an opportunity and they are probably at a point where they might want it more than me, that full-time gig, so it’s only fair I think to give someone else that opportunity."
