Kienan said his teacher, Amy Shing, entered him and his classmates for the competition.
"She gave us the designs and told us all about it, then we designed them and sent them off," he said.
"I was amazed that mine was one of the top three. Usually when I enter a competition I just enter but don't really care because there are a lot of other schools out there."
He said he was up all night finishing his design before entering.
We didn't finish it [at school] so we had to do it for homework and I was up all night. I was looking up heaps of patterns on the internet.
After making the top three he had to get as many votes on Facebook as possible, ending up with 677 votes.
"I finished school on Friday not knowing how I was doing.
"Mum picked me up and I asked for her phone to check on the votes. I saw I was leading but the other boy was gaining on me fast. We sat [mum and I] on the couch watching the likes go up and the time tick on. Then 4pm hit and I won. I was jumping like crazy around the lounge yelling 'I won mum, I won'."
The front of the jersey includes a range of features from across the Bay.
I have drawn the hills as an optical illusion to represent the mountains of the Bay of Plenty.
I have drawn a wave look to represent all the beaches around Bay of Plenty. I have drawn two koru patterns on the side of the jersey to represent Hinemoa and Tutanekai.
I have drawn a heart at the top of the jersey which represents the love for Bay of Plenty.
On the back he has included loads of circular patterns which represent the Rotorua mud pools and geothermal areas across the Bay.
Kienan will receive one of the jerseys signed by the 2014 Steamers team. He will also have the option of receiving his jersey at halftime during the Otago match at ASB Stadium.
Ms Shing said he was very creative and had gone above and beyond with his design.
"He is very creative and very enthusiastic and puts 100 per cent into everything. And he has such a passion for rugby," she said.
Shing said her entire class had been given tickets to an ITM Cup match because of the quality of their designs.
Kienan started playing rugby last year and plays halfback for Kahukura. He would like to play for the Steamers some day.
The alternative jersey will be available online for pre-sale this week, www.boprugby.co.nz/supporters-zone/tickets--merchandise, but only for a short time.