The defender joins from national powerhouse and 13-time continental champion Auckland City, bringing significant big-stage experience.
His thumping header against Argentine giants Boca Juniors at last year’s Club World Cup helped the amateur side secure a stunning draw.
Gray also played against German champions Bayern Munich, marking star English striker Harry Kane, and dealt with Uruguayan forward Edinson Cavani when facing Boca.
“Down here in New Zealand we’re so far away from it, but football in Argentina in particular is huge,” he said.
“From that one moment, it (his following) went up pretty much overnight. It's probably gone down a little bit since then, but before that my social media was non-existent to be honest.”
Gray is South Island United’s 21st and final signing and, at 29, the oldest player in what is otherwise a young squad.
With several years of experience playing in the Pacific Islands for Auckland City, Gray hopes he can help his new teammates with his expertise.
“I’ve played in most of (the islands), it is a different challenge over there,” he said.
“The conditions play a massive part, and how you manage the game and manage yourself in those conditions, that's probably the main thing.”
Gray has just finished a teaching degree and was due to start full-time work at Auckland Grammar before being offered a professional deal by South Island United.
“I was locked in for this year as a teacher, and I was ready just to get stuck into that career until I got a call from South Island United and I considered it.
“The school was supportive and said ‘yeah go do that, you can come back after’. To be part of a brand-new club and a brand-new league I thought yeah, I’ll do it.”
Gray is looking forward to playing in front of friends and family when he runs out for United’s first game on January 17, at Eden Park against Auckland FC.
“It will be cool to represent the South Island against Auckland, hopefully there’s a decent crowd and atmosphere – obviously Eden Park is exciting.
“Being a brand new league and a brand new club, there’s a little bit of uncertainty I guess, but who knows?
“I’d like to think we have a good chance at the title,” he said.
