After leaving Chelsea Art College in London, where he studied film and Fine Art Painting, McCarthy decided to become a full-time Artist. He created the independent comic book Sometime Stories with art college pal Brett Ewins. His first paid commercial work was a one-page strip Electrick Hoax in the British weekly music paper Sounds with another art school escapee, Writer Peter Milligan in 1978. McCarthy held a solo exhibition of paintings, drawings and collages at Car Breaker Gallery in London, a squat in Ladbroke Grove's Republic of Frestonia.
In 1983 McCarthy collaborated with Peter Milligan and Brett Ewins on Strange Days, an anthology title published by Eclipse Comics. He also drew a two issue series featuring his alternative media-brat superhero Paradax from Strange Days.
McCarthy designed the characters in Grant Morrison's Zenith strip which started in 1987, Doom Patrol (creating Danny The Street) and on Morrison and Mark Millar's Marvel series Skrull Kill Krew. He also produced covers and character designs for Pete Milligan's revamp of Shade, the Changing Man.
McCarthy spent much of the remainder of the 1990s working in film and television, most notably as the production designer of the international hit CGI animated science fiction TV series ReBoot and as the character creator for War Planets.
Brendan returned to 2000 AD in 2010 on a Judge Dredd story with Al Ewing spoofing the Dr Who TV series, and with whom he would go on to create a popular new story, The Zaucer of Zilk, which he has described as a cross between Harry Potter and Aladdin Sane: "A glammatronic phantasmagoria." The series debuted in March 2012. It was rapidly reprinted by IDW in a new format with both issues quickly selling out. The Zaucer of Zilk comic appeared in many 'best of the year' lists.
In 2004 McCarthy created an illustrated visual autobiography of his original art and design work titled Swimini Purpose. This was released in 2005 in the UK, as a limited artist's edition.
In 2006, McCarthy was featured in the final issue of DC Comics' Solo. His comic had new takes on characters such as The Flash, Batman, and Johnny Sorrow and he considers the single issue to be one of his best works.
In 2009, Brendan was commissioned by Marvel Comics to create a new take on Doctor Strange. The bizarre mini-series, Spider-Man: Fever, appeared in April 2010.
In 2012, McCarthy traveled to Namibia in Africa, to visit the set of Mad Max: Fury Road, which featured his script and designs. He also finished the design and editorial chores for The Best of Milligan & McCarthy, a brand new collection of his most famous comic works co-created with Peter Milligan. Dark Horse released the edition in September 2013.
Mad Max Fury Road was finally released in May 2015. McCarthy attended the Hollywood premiere. The film received many 'Best of the Year' awards including six Oscars. It was McCarthy's first Hollywood screenplay, and he was the original Production Designer on the movie.
McCarthy's new graphic novel "Dream Gang" for Dark Horse Comics was released in July 2016.
A collection of his classic Judge Dredd stories from over 35 years of work was collected by IDW in hardcover and released in January 2017.
