In 2003, his first two books in the Mad Grandad series for younger readers were released by the O'Brien Press of Dublin, followed by his first young adult novel, The Gods and their Machines in 2004.

The Harvest Tide Project was actually the first novel McGann had written, but it was contracted as part of a three-novel deal, and his publishers chose to release The Gods and their Machines first.

In May 2007, Small-Minded Giants was recommended by the Education Secretary, Alan Johnson and the School Library Association in the UK on a one-off list of Top 160 Books For Boys.

In November 2010, an extract from Small-Minded Giants was used as part of paper one of the English GCSE, By the Northern Ireland Council For the Curriculum, Exams and Awards (CCEA).

In 2012, he was commissioned to write a young children's book, published as "The Wolfling's Bite", as part of "The Nightmare Club" series, by Little Island, under the pseudonym, "Annie Graves".

In 2014, Penguin published two novels, "War's Harvest" and "Cruel Salvation", which he was commissioned to write, to tie in with the medieval fantasy online game, "Kings of the Realm".

2011: The French edition of Ancient Appetites, Voraces, shortlisted for le Grand Prix de l'Imaginaire in the Young Adult (Foreign) Novel category.

2012: "The Wildenstern Saga" as a series, long-listed (one of ten titles) for the Grand Prix de l'Imaginaire in the Young Adult (Foreign) Novel category.