At university he studied electrical engineering, moved to London in 1999 and worked there for two years as a computer programmer in an investment bank before quitting that job to become an artist.
[3] In 2011 he took part in the successful group effort to break the Guinness World Records for the fastest comic-book ever produced and the largest number of creators working on a single comic, with proceeds going to Yorkhill Hospital.
[6] It was announced at the 2015 San Diego Comic-Con that Baillie would write a new series for Vertigo called Red Thorn, set in modern day Glasgow exploring Scottish mythology, featuring art by Meghan Hetrick, colours by Steve Oliff, (latterly Nick Filardi) and letters by Todd Klein.
[7] In 2017 Baillie appeared at the Edinburgh International Book Festival with Rob Davis to discuss Comics of a Deadly Kind and the inspiration and publication history of his series Red Thorn.
[10] In 2019 Baillie's Chopper stories were collected by Rebellion and he wrote a graphic novel celebrating the thrash metal band Megadeth's greatest hits international tour.