James won $12,000 in prizes.
The Massey University graduate is looking forward to taking on two of his former flatmates in the grand final.
"My old flatmates Hamish Best and Richard French will represent the East Coast and Waikato/Bay of Plenty regions respectively."
Second place in the regional final went to Rongotea farmer Nigel Will. Toko's Nick Brown was third.
Nick, who's the chairman of Central Taranaki Young Famers, won the Massey University Agri-Growth Challenge and the highly-contested Agri-Sports.
"I really enjoyed the experience," said Nick, who's a sheep and beef farmer.
"I'm glad one of my fellow Taranaki competitors has made it through to the grand final. It's been a while since that happened and is great news for our district."
During the Agri-Sports Challenge, finalists had to put wheels on a quad bike, erect a Taranaki gate, sew a button onto a shirt, service a piece of milking equipment and lasso a wooden gumboot.
The eight finalists used chainsaws to carve the gumboots earlier in the day.
"Nick Brown could definitely have a career as a chainsaw artist after this," said host Te Radar. "His attention to detail is admirable."
The TeenAg competition was unprecedented, with five teams all from Feilding High School, facing off against each other. A team from Hiwinui School took out the AgriKids regional final.