He has published fourteen books and numerous academic articles on maritime and naval history.
Public history
Since 2017, Willis has co-organised and delivered several onsite lectures in The History Masterclass project, a series of seminar sessions delivered by well-known public historians.
Television and media career
He made numerous appearances on TV and Radio as an expert contributor before he presented Nelson's Caribbean Hell-Hole, a 2012 film for BBC4 about the excavation of a mass burial site near the British naval dockyard at English Harbour in Antigua. In 2013 he presented a three-part series for BBC4 on the cultural history of Shipwrecks and was one of the nine-man crew that recreated John Wesley Powell's epic uncharted 1869 voyage down the Colorado River through the Grand Canyon in Whitehall boats, that was filmed and broadcast by BBC2 in January 2014. In October 2014 he presented a three-part series on Castles for BBC4: Castles: Britain's Fortified History. In October 2015 he presented another three-part series for BBC4 Britain's Outlaws: Highwaymen, Pirates & Rogues. In 2016 the BBC broadcast The Silk Road, a series following Willis's journey from Xi'an to Venice. Willis's first series for National Geographic, Nazi Weird War Two, was broadcast in December 2016. The show in which Willis teams up with Robert Joe, an Urban Explorer, has been described as 'one of the oddest partnerships since Mulder and Scully'. Since 2016, Willis has hosted the Histories of the Unexpected podcast with Professor James Daybell, with a book based on the series published by Atlantic Books in 2018. The podcast is part of the "History Hit Network", created by Dan Snow, with whom Willis had travelled down the Grand Canyon. In early 2017 Willis presented another three-part series on the evolution of British arms and weaponry, in the same format as his 2014 series on castles, again for BBC4: Sword, Musket and Machine Gun: Britain's Armed History. In 2017 Willis presented two other 3-part TV series: Maritime Silk Road Reborn for National Geographic and Invasion! for BBC Four.
Publications
His first book, Fighting at Sea in the Eighteenth Century: The Art of Sailing Warfare was based on his PhD thesis and was a revisionist study of the history of tactics in the Age of Sail. It explained in greater detail than ever before how battles were won or lost in the Age of Sail. His subsequent books include the Hearts of Oak Trilogy and the Fighting Ships series. In 2011 he was awarded the Society for Nautical Research's Anderson Medal for his biography of the naval battle The Glorious First of June, the final instalment of his Hearts of Oak Trilogy. In 2010 he made a discovery in the British Library of previously unpublished naval dispatches from the French Revolutionary and Napoleonic Wars which became the subject of his 2013 book, In The Hour of Victory.
Fighting at Sea in the Eighteenth Century: the Art of Sailing Warfare, Woodbridge, 2008
Shipwrecks: A History of Disasters at Sea, London 2009,
Fighting Ships from the Ancient World to 1750, London 2010,