His first book, Walking With the Anzacs: A Guide to Australian Battlefields on the Western Front, was published by Hachette Australia in February 2007.
In 2007 McLachlan produced the documentary Lost in Flanders, which follows the investigation into the identities of five Australian soldiers uncovered on the First World War battlefields of Belgium.
McLachlan is also a regular presenter on The History Channel, a history commentator on Channel Seven's Sunrise program and regularly appears in print and on other television and radio programs.
[2] In 2013 McLachlan hosted the 7-part National Geographic Series Australia: Life on the Edge, which was nominated for an ASTRA award for Best Factual Program.
He has appeared in numerous other TV programs including Tony Robinsons World War One and Who Do You Think You Are.