Cornell's professional writing career began in 1990 when he was a winner in a young writers' competition and his entry,
Kingdom Come, was produced and screened on
BBC Two. Soon after, he wrote
Timewyrm: Revelation, a novel for the
Virgin New Adventures series of
Doctor Who novels.
Timewyrm: Revelation was a reworking of a serialised
fan fiction piece Cornell had penned previously for the
fanzine Queen Bat. Several other
Doctor Who novels followed, including
Human Nature. Cornell then began working for
Granada Television, where he wrote for the children's medical drama ''
Children's Ward'' and created his own children's series
Wavelength for
Yorkshire Television, which ran for two series. He made the crossover to working in adult television full-time in 1996, when he was one of the main contributors to Granada's supernatural soap opera
Springhill, which ran for two years on
Sky One and later on
Channel 4. After a short stint on
Coronation Street, he began working for other production companies, including contributing an episode in 1999 to
Red Production Company's anthology drama series
Love in the 21st Century for Channel 4. His episode, entitled
Masturbation, starred
Ioan Gruffudd as Jack. He was due to be one of the writers on Red Production Company's planned
Queer as Folk spin-off series
Misfits, but the series was never made, being cancelled by Channel 4. In the 21st century he has written mainly for the
BBC, contributing episodes to all three of their regular medical dramas:
Casualty,
Holby City and the daytime soap opera
Doctors. He also contributed to the 1950s-set Sunday evening prime time drama series
Born and Bred and was one of the writers of the 2005 series revival of
Doctor Who, writing the episode "
Father's Day". The episode was nominated for the
Hugo Award for Best Dramatic Presentation, Short Form in 2006 and came third in terms of votes for its category. Cornell later wrote a two-part story for
Doctor Who's 2007 series, based on his 1995
Virgin New Adventures novel
Human Nature. The title of the first episode was also "
Human Nature", while the second was titled "
The Family of Blood". In 2008, the two episodes were nominated for the
Hugo Award for Best Dramatic Presentation, Short Form. In February 2006, Cornell announced in a post on his weblog that he would be writing an episode for the BBC's
Robin Hood, produced by
Tiger Aspect Productions for the same Saturday evening family slot as
Doctor Who. He later announced that he was also writing a second
Robin Hood episode for later in the first series. His first episode, "
Who Shot the Sheriff?", aired on BBC One on 21 October 2006. His second, "
A Thing or Two About Loyalty", followed on 2 December 2006. He also wrote an episode for the second season of another Saturday evening family adventure programme, the ITV science-fiction series
Primeval, transmitted in February 2008. He also wrote the one-off pilot
Pulse, which was shown on
BBC Three in early June 2010. Outside of television, he has been active in various other media, having written six
Doctor Who novels for
Virgin Publishing and
BBC Books during the 1990s, three
Doctor Who audio dramas for Big Finish Productions and a fully animated internet-broadcast
Doctor Who adventure,
Scream of the Shalka (starring
Richard E. Grant as the Doctor) for
bbc.co.uk in 2003. He has also written two mainstream science-fiction novels,
Something More and
British Summertime for
Gollancz, and various novels, short stories and audio dramas based around a character he created for the
New Adventures, Professor
Bernice Summerfield, and whom he later licensed to Big Finish Productions. He has also co-authored (often working with
Keith Topping and
Martin Day) several non-fiction books on television, including
The Guinness Book of Classic British TV,
X-treme Possibilities (a guide to
The X-Files), and
The Discontinuity Guide (a humorous guide to
Doctor Who). (Topping and Day's
Doctor Who novel
The Devil Goblins from Neptune was also based on an original idea with Cornell.) He has also written comics, both for
Doctor Who Magazine and the
2000 AD spin-off
Judge Dredd Megazine. He has written
Wisdom, a 6-issue
limited series for
Marvel Comics'
MAX imprint, featuring the character
Peter Wisdom, with art by
Trevor Hairsine and
Manuel Garcia. It was announced at the 2007
Wizard World Chicago comic book convention that Cornell would be following
Chris Claremont on Marvel's
New Excalibur. Plans were subsequently changed with the cancellation of the
New Excalibur title and Cornell's new project was announced as being titled
Captain Britain and MI: 13. The third
trade paperback,
Vampire State, was nominated for the 2010 "
Best Graphic Story"
Hugo Award. Cornell has also written
Young Avengers Presents No. 4 (April 2008) and a
Fantastic Four mini-series comic,
True Story, which started in July 2008, which featured the team encountering characters from the pages of literary classics. In 2008, he wrote a comic which featured on the Doctor Who website. He has also written the
Young Avengers limited series that ties into
Dark Reign and
Black Widow: Deadly Origin a mini-series that ties into the character's appearance in
Iron Man 2. Cornell became the next
Action Comics writer after
War of the Supermen. Cornell signed with DC Comics exclusively in 2010 as part of writing for
Action Comics. His 16-issue run on the series included number 900. In late 2010 and early 2011, Cornell completed nine issues set in Batman's world:
Knight & Squire, a six-issue miniseries, and a three-issue run in
Batman & Robin, #17–19. In September 2011, as part of DC's
The New 52 relaunch, Cornell became the writer for the DC Comics titles
Demon Knights and
Stormwatch. Cornell's last DC work was the 14-issue science fiction series
Saucer Country, which ended with the June 2013 issue. Cornell is part of the regular panel of the podcast
SF Squeecast, which won the 2012 and 2013 Hugo Award for best fancast. In January 2016, Cornell announced his return to television drama work with his first script for US television, contributing an episode to the
CBS Sherlock Holmes series
Elementary. In 2018, he started co-hosting (with Lizbeth Myles from the
Verity! podcast) a podcast reviewing horror films made by
Hammer Film Productions entitled Hammer House of Podcast. ==Personal life==