Famous for his time as the lead designer for animation on the popular Cartoon Network TV series Adventure Time. He has also garnered fame as a published illustrator, and saw his 2017 book The Gold Leaf be named one of Globe & Mail's top 100 books of 2017.
He had his first book, a comic called Ojingogo, released in 2004. He was twice nominated for an Eisner Award for his illustrative work on the book in 2004 and 2005.
His debut illustrated children's book My Name is Elizabeth was named a New York Times Notable Picture Book in 2011. He had his ninth illustrative book The Brilliant Deep released in 2018.
He was born and raised in Welland, Canada.
He and Daniel Handler worked together on the 2017 children's book The Bad Mood and the Stick.