Lachlan is a Sessional Staff member at Victoria University, Melbourne. Since 2011, he has also taught at Swinburne University of Technology. He is an historian whose research interests include anti-communism, security and intelligence, nuclear power and weapons, Aboriginal affairs and Australian political history.
Lachlan completed a Bachelor of Arts (Honours) in 2006, receiving first class honours for his thesis, titled The Petrov Affair and the 1954 Election. His PhD thesis, completed in 2010, was titled Australian Cold Warrior: the Anti-Communism of W. C. Wentworth.
His 2010 paper (published in 2011), Fighting the Enemy Within: Anti-Communism and Aboriginal Affairs, was shortlisted and commended by the judges in the 2010 AHA/CAL Postgraduate History Prize. In 2011 he was awarded the Most Outstanding Final Year Research Student Award in Victoria University's School of Social Sciences and Psychology. He was also awarded the 2011 Moran Award for the History of Australian Science Research, administered by the Australian Academy of Science at the Basser Library, Canberra. He has published several academic journal articles on Australian politics during the Cold War, often with a focus on W. C. Wentworth - the subject of his PhD thesis.
He is currently working on a book with Ross Fitzgerald on communist espionage in Australia, titled 'A Dozen Soviet Spies Down Under', to be published by Connor Court (Melbourne) in 2015.