Through Terroir Selections, Banks owns and distributes some of California's highest profile wineries including Mayacamas, California's oldest cabernet producer. He also owns leading South African winery Mulderbosch.
"Trinity Hill is in a terrific position to prosper having consistently delivered high quality wines across its range," Banks said in a statement.
"We intend to invest the necessary capital to allow the continued improvement in quality," he said.
Trinity Hill's chairman and co-founder Robyn Wilson said the acquisition meant the company would be able to get its flagship wines the Homage and The Gimblett on to US wine lists.
Wilson, a London-based New Zealander who owns London's Bleeding Heart Restaurant Group, said Banks's move would allow Trinity Hill to develop in more areas.
Trinity Hill was established in 1993 and had its first vintage in 1997.