Queenslander McKain, along with Newcastle Jets defender Andrew Durante, were confirmed as Phoenix signings today.
The signing of McKain proved the worth of a scouting mission to Europe undertaken by football chief Tony Pignata and Phoenix head coach Ricki Herbert.
"I don't think we would have been able to secure the services of Jon without being on the ground in Europe," Pignata said. "The trip allowed us to touch base directly with players and agents to ensure deals were done promptly and properly. It was certainly a very worthwhile exercise and Jon's signature is proof of that."
McKain joins Phoenix from Romania's Timisoara and chose Wellington over a lucrative rival offer from cashed-up FC Cluj.
The defender was introduced to senior football by current Queensland Roar coach Frank Farina and also would have been an ideal first signing for Gold Coast Galaxy, whose outspoken football director Miron Bleiberg appears more focused on signing veteran A-League free agents.