Punters lapped up the chance to rub shoulders with some of the game's biggest stars, including Johnson's Warriors teammate Roger Tuivasa-Sheck.
There were long queues for autograph signing sessions and the chance to grab "selfie" photographs with players from the 16 NRL teams including Aussie sides Melbourne Storm, Gold Coast Titans, Brisbane Broncos and the Parramatta Eels.
Warriors fan Jamie O'Brien travelled from Hamilton with his 10-year-old son Caleb to soak up the atmosphere.
"Caleb hardly slept a wink last night because he was so excited about meeting the players," Mr O'Brien said. "It is outstanding that I can bring my kid along to say hello to the likes of Shaun Johnson.
"We will be here for the entire tournament and this was a great way to start the trip."
George Smyth, 28, and girlfriend Sammie Taylor, 24, from Taupo, hope the Warriors will rule.
"I don't want to jinx my team but I feel we are going to win it," Mr Smyth said. "The Fan Day has been a great way to get us in the mood."
Duco Events chief executive Martin Snedden believed part of the ongoing success of the Auckland Nines was the excitement leading in.
"Auckland really turns it on for the Auckland Nines," Mr Snedden said. "Events like the Fan Day create a buzz in the city, and New Zealand and overseas fans get to meet their rugby league heroes."
Tuivasa-Sheck said it was a "buzz" to meet so many supporters face-to-face. "I've been signing things for people from all over the world and this is perfect for setting the scene for the tournament for the players as well as the fans," he said.
"We are very excited about the tournament and the prospect of the Warriors playing together again as a team," he said.
"Having Shaun back as captain has also given us a real boost."
