Students in his Year 6 class all created their own designs, with teacher Annie Riley sending the best three through to be judged.
"They are a bit older, so I knew that they could take on the challenge. It is awesome that Cassius was selected."
As a school, she said they were going to buy new sports equipment with the money.
"As a low decile school, we struggle with that sort of stuff, so it is really nice to be able to buy some new equipment."
Cassius' mum Lauren Marsh said they were "very proud of him".
"We didn't know he had been entered or that the school was doing it until they phoned me to let us know he had come second, about two months ago."
He loves to draw pictures at home - something he got off his "artistic" father, she said.
On November 1, they went with two of his siblings and bought a hot chocolate in his cup.
Director of The Coffee Club, Brad Jacobs, said, "We're into our fourth year of supporting KidsCan with the Christmas Cup Art Competition, and it's one of the things we're most proud of.
"We always get great entries and it's pretty cool for us to be able to put out the winning designs for other people to enjoy. We added a new 'highly commended' category this year so we could recognise even more of the kids and their artistic efforts.
"We were supposed to award five but had to give out six in the end as the quality of work was just so high."
KidsCan CEO and founder Julie Chapman said they were "really thankful to The Coffee Club for their support in making this happen and raising awareness of KidsCan and the wonderful students we support".
"We really love the Christmas Cup Competition and we're so proud of the clearly talented children going to our KidsCan schools.
"The cups really are pieces of art! It's great to get so many children involved in something which encourages them to be creative, while also drawing attention to our charity which has been helping create brighter futures for Kiwi kids since 2005."
The Christmas Cup competition aims to raise awareness of the work being done by KidsCan to support the education, health and wellbeing of children living in hardship. Now in its fourth year, it has seen more than $40,000 donated to schools and the kids by The Coffee Club in that time.
The five young artists each received $250 Westfield vouchers. The six highly commended entrants, which included children from Auckland, Taupo and Levin, were each given $500 for their schools and $100 in vouchers for themselves.
For more information on KidsCan, including information on how you can get involved either as an individual or business, please visit the website kidscan.org.nz. For more information on The Coffee Club New Zealand please visit thecoffeeclub.co.nz.