"The transaction effectively managed and communicated several complexities including dual-country regulatory approvals, related-party issues and a time-based price escalator," the judges said.
Synlait Farms Holdings is majority-owned by Shanghai Pengxin, which also acquired the North Island Crafar Farms in 2012.
Toby King, of Cameron Partners, said the award was a tribute to the Synlait Farms asset and its team.
"We all know that good product sells and good product means a good asset, good team and good information.
"The odds always seem stacked up against you but occasionally the clouds peel open, the sun shines, the grass grows and it feels as though you're the dealer with the stacked deck."
The other finalists were Arvida Group's $329 million aggregation of 17 retirement villages and the sale of Transpacific Industries NZ to Beijing Capital Group for $950 million.