He was chasing a success of a different kind.
O'Connor slotted straight into the heart of his home club's senior football team, and starred in their quarter final win over Dr. Crokes. Dingle came closer than anyone to East Kerry then, when they were beaten by one point in the semi-final.
But O'Connor's club-mate Paul Geaney says that the AFL star's impact was transformative, and that his growth as an athlete, from the youngster that left in 2016, to the 6 ft 3 inch giant he is now, was a sight to behold.
"When he left, he was just out of minor," says Geaney, at the launch of the 2023 Allianz Leagues.
"He returned for us in 2018, and played a half for us against Austin Stacks, and that turned our season and we went onto the county final.
"The changes were apparent then in him physically maturing.
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"Now he's a professional athlete for nearly seven years now, so he's a serious specimen, and he's 6 ft 3 as well so he's an incredible athlete."
O'Connor won All-Ireland minor titles for Kerry in 2014 and 2015, the second as captain, and back then it was hoped that he would be a Kerry midfielder for years to come.
"He was (an incredible athlete) before he went out there too but he's turned into an animal of a different nature now," added Geaney.
"I think there was a picture going around there recently of Geelong's pre-season and his arms were bulging and the picture did the rounds, but we'd love to have him going forward at some stage.
"I'm not sure what his circumstances will be, if we can get him for the club season it would be great because he's a massive addition to a small club."
Some of O'Connor's Geelong team-mates came over for that Crokes game, and Geaney was struck by their togetherness when they visited his pub in Dingle.
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"A few of them came around for the Dr Crokes game, the county championship quarter-final.
"They were on a visiting tour. They came in and watched the game, and were around afterwards. Zach Tuohy was around on a different day, the East Kerry semi-final. They are well bonded!
"They are very good in Australia for creating real bonds in their set-ups, which you probably wouldn’t have as much in the other professional set-ups."
For Geaney, this week was something of a sad one as he had to say goodbye to his long-time team-mate David Moran who, after 14 years in the green and gold, decided to hang up his boots.
"He'll be a Kerins O'Rahilly's forward's dream now from here on," says Geaney.
"I could go on about him all day," adds Geaney, "but I can understand where he was coming from.
"I'd feel a lot better now," he adds with a laugh, "if it wasn't the rhetoric going forward now that Geaney is the oldest!"
Geaney is 32 now, but he says he has no plans for retiring soon. Having his son Páidí, his 'biggest supporter' with him every step is surely a big motivation in that sense.
"He was on the field with me in 2019 after the replay loss, but he was just three then and maybe too young to understand it, but this time around , he fully knew what was going on and he's probably my biggest supporter.
"So it was nice to bring him out on the field after the All-Ireland win win.
"He was the talk of the school obviously, going into senior infants the month after, and when we brought in the cup too, he was the talk of the class! That was nice for him. But his interest is probably only really starting to pique with football now.
"He didn't have too much interest in football before but it's starting to turn a little bit and it's probably an age thing.
When they're younger, they're playing games and cartoons and stuff, but he's getting into the football now, going to the games with Siún so, his class-mates are getting into it now as well. Some of them are football mad! He might get sick of it in time."
After all the pre-season clashes, the real stuff kicks off this weekend when Kerry travel to Donegal for the first round of the National League. Dingle to Ballybofey is a six hour journey but Geaney says Kerry will travel up on the Saturday, and that trips like these are great for team bonding.
"Most other teams would travel on the day of the game because they're midlands or otherwise. Whereas with us at the moment there's no Munster team in Division 1. Even Kildare and Dublin are gone.
"So our closest trips are Galway followed by Mayo and Roscommon which are still four or five hours from Dingle so we travel the day previous and you get time to bond and great relationships with your team-mates which is valuable as well. Donegal is probably up there with the longest."
Geaney himself will miss the first couple of games due to an ankle procedure but it's clear by him, if nothing else, that this man is raring for road again.
"I had a small procedure done there just before Christmas on my ankle so Im not fully back yet. I'll be back in a couple of weeks time hopefully, but I'm on the sidelines for the time being. It could be shorter than the prescribed or it could be longer.
"The team as a whole, the days of wintering well are gone. With the club season for most fellas going into November and then most fellas keep themselves in good shape so the work to get back isn't hectic.
But, at the same time, to get to where you want to get to, it's still a steep incline. No doubt they'll get there in the next while. They look to be working hard at the moment in getting there.
"Hopefully there aren't too many hard, wintry sessions of old to come."
