The NRL estimates around $1 million has been raised for Arrow since May, when a motor neurone disease (MND) diagnosis forced the South Sydney star to hang up the boots.
His 31st birthday coinciding with Sunday's clash between Souths and Newcastle, Arrow was thrown the "world's biggest birthday party" by the NRL.
Queenslander Arrow was on hand, in the same week as he married long-term partner Berina and attended Wednesday night's State of Origin decider.
"I honestly can't thank the NRL and South Sydney enough for everything they have done," Arrow said after the Rabbitohs' 26-24 win.
Speaking of his battle with the insidious MND, Arrow pledged to "fight, and continue until I have no more left in me".Â
"I refuse to give up," he said.
"For anyone out there with MND, you're not alone and I am with you."
Hundreds of fans queued up in party hats waiting for Accor Stadium's gates to open at 12.30pm, while others secured theirs on entry.
The league will submit footage to the Guinness Book of World Records for assessment, but are confident of having broken the record for largest gathering of people wearing party hats.
Set last year at Ohio State University, the standing record is 1,924 people, and the NRL printed around 10,000 hats to distribute for Sunday's game.
Sunday's game-day raffle was pledged to Arrow and his family, with the visiting Knights making a donation as well.
The Wiggles performed live entertainment at halftime, when officials rolled out a giant 120kg birthday cake in the shape of Arrow's old Souths jersey.
Prime Minister and lifelong Rabbitohs fan Anthony Albanese was on hand as the cake was cut and 'Happy Birthday' was sung.
But the most jubilant scenes were saved for after the Rabbitohs' upset win, with the crowd of 30,113 permitted onto the field to celebrate.
Souths chief executive Blake Solly and Australian Rugby League Commission chair Peter V'landys presented Arrow with his birthday present - a commemorative framed jersey.
Arrow thanked the crowd after the presentation, receiving rapturous applause.
"It was a magnificent crowd - generous," said Souths coach Wayne Bennett.
"I just met the Wiggles in there (the dressing rooms). I've listened to a lot of their songs through my children. I wanted to sing a couple to them but they weren't really interested in that.
"It's lovely, people have put themselves out, done special things for him."
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