Brigadier McLachlan has had a 30-year career within Defence, primarily in the land engineering. In 2017 he was appointed as the Technical Regulator Authority – Land where he was responsible for the regulation of Land Materiel in Defence. In 2022 Brigadier McLachlan was appointed as the inaugural Director General Landworthiness, where he is responsible for the development and assurance of internal to Defence regulations within the land domain. He has twice been awarded a Conspicuous Service Cross for his work in engineering and land regulation. Brigadier McLachlan holds degrees in Science and Engineering and a Masters in Systems Engineering, he is currently studying a Masters in Law.