Once a professional squash player, the PGG Wrightson technical field representative and East Coast representative also won the Agri Skills Award at the grand final.
The winner, Jarman, said he was feeling overwhelmed, excited and relieved that it's over.
"I'm just also so incredibly thankful to so many people, far too many to name but it's a huge team of people to pull together this event and a big team behind me to get me here too."
Jarman said he was determined to give the grand final his best shot after initially signing up to the contest to just give it a go.
"I was happy that I gave everything a go to the best of my ability and was competitive. I loved the practical day, the challenge of having to multitask under time pressure and be a bit strategic."
He said he never dreamed he'd win the title of FMG Young Farmer of the Year but was immensely proud of the achievement and hoped it would inspire others.
The victory was a culmination of days of gruelling practical and technical challenges set out to test the seven grand finalists' skills, knowledge and stamina.
Contestants took part in a technical day, a practical day, speeches, exams and the famous FMG Young Farmer of the Year buzzer quiz.
Jarman won a prize package worth more than $75,000 which included a $15,000 cash prize from FMG, a Honda ATV, and a $30,000 package from New Holland.
"My fellow competitors certainly didn't make it easy and honestly, I feel like it was anyone's game for the whole three days. It's been a privilege getting to know them and to now call them friends."
Jarman also won the Agribusiness, Agri Sports and Agri Knowledge awards.
Whangarei Young Farmer Calvin Ball, 31, took out third place and also won the Community Footprint award
"I put my absolute best into this, I made so many sacrifices and I'm so proud of how I competed, but at the end of the day there was seven amazing competitors, so big ups to Joseph and Jake who pipped me but I'm very grateful and proud of what I've achieved during this experience."
