As an illustrator and writer of children's books Joel is known internationally for his Dexter Bexley picture books, and his illustrations for contemporary authors such as Pam Ayres,  Julia Donaldson, Carol Ann Duffy, Michael Rosen, Roald Dahl, and Michael Bond, and classic texts by authors such as Hans Christian Andersen, and Lewis Carroll. With Steve Roberts he is co-creator and co-artist/writer of the Tangletree Mysteries series of comics for young readers.

Joel Stewart's paintings drawing on a range of traditional techniques and a lifelong love of drawing. They are a personal exploration of place, colour, gesture, emotion, improvisation, depiction and abstraction. 

Joel is the creator/director of the hit CBeebies children's animation series The Adventures of Abney & Teal, which he created, co-wrote, and directed under the guidance of Anne Wood and Ragdoll Productions LTD (creators of Tellytubbies, Twirlywoos, Dip Dap, and In the Night Garden amongst many others).  

Prior to, and during, lockdown 2020 Joel co-created and co-directed with Steve Roberts (Twirlywoos, Dip Dap) and Anne Wood, the animation series B.O.T. and the BEASTIES for CBeebies and BBC television. 

Joel contributed to the creation of songs and music for both B.O.T and Abney & Teal. He also makes and repairs instruments.

Joel's awards for illustration include:
Macmillan prize for children's book illustration in 2000.
Silver medal, Parents Choice, 2002, for The Adventures of a Nose.
Selected for the IBBY Honour List for outstanding book illustration work in 2006 for Tales of Hans Christian Andersen.
Winner of 0-5 Nestle Bronze award 2007 for Dexter Bexley & the Big Blue Beastie.
Chosen by Booktrust in 2008 as one of the ten best new illustrators of the last decade.