COL Lambert graduated in law from the Queensland University of Technology in 1990 and has been admitted as a barrister and solicitor of the Supreme Court of Queensland, the Supreme Court of the Australian Capital Territory and the High Court of Australia. Prior to joining the Australian Army Legal Corps in 1991 he worked in the Queensland Government for 7 years. During his early service he was posted to HQ 1 MD (Brisbane), HQ 3 MD (Melbourne), Defence Centre Melbourne, BASC Puckapunyal and the Directorate of Army Legal Services in Canberra.


From 1997 to 2001, he was posted as the brigade legal officer to both HQ 7 BDE (Brisbane) and HQ 3 BDE (Townsville). While at HQ 3 BDE, COL Lambert undertook operational service in East Timor as part of INTERFET and was the chief legal adviser to commander Deployable Joint Force Headquarters during OP PLUMBOB (Fiji). During that time he also deployed to Bougainville and Malaysia to act as counsel assisting in a number of high profile administrative inquiries.


From 2002 to 2003, COL Lambert served on exchange with the British Army. During that time he performed duties on various NATO and Permanent Joint Force Headquarters exercises in the United Kingdom, Germany and Gibraltar. He also presented the rules of engagement component of the outreach program to the partnership for peace nations in Sofia, Bulgaria. In addition, he was deployed to Multinational Division (South East) Basrah, Iraq on OP CATALYST to provide advice on rule of law and anti-oil smuggling operations.


On his return to Australia in 2004, COL Lambert was posted as the Deputy Director of Military Administrative Law in the Defence Legal Office in Canberra. From 2005 to 2006 he performed out of corps duties as the SO1 Personnel Operations–Army and managed serious, sensitive and complex personnel related incidents and complaints. From 2007 to 2008 he was posted to the office of the Chief of Army and for part of that time was appointed as the Director of Army Legal Services. From 2009 to 2011 COL Lambert was posted into the tri-service environment as the Director of Legal Review in the Office of the Inspector General Australian Defence Force (IGADF) and provided advice on serious and complex military justice issues. 


In 2012 COL Lambert was posted as the command legal officer to Special Operations Command and deployed to Tarin Kowt, Afghanistan on OP SLIPPER with the Special Operations Task Group providing advice on incident management, targeting, detainee management and rule of law. In 2013 he was awarded the Conspicuous Service Cross for his contribution in the advancement of administrative law practices in the ADF.


From 2013 to 2015, COL Lambert was posted as the Director Military Justice Performance Review in the Office of the IGADF and was responsible for conducting military justice audits of ADF units, ships and establishments and reviewing the performance of the entire military justice system by collecting and analysing military justice information, material and statistics to determine military justice trends.


In 2016, COL Lambert was appointed by CDF as the Director of Defence Counsel Services and in that role was responsible for the management and provision of legal support to individuals subject to action under the military justice system.  


COL Lambert has also successfully completed the Joint Operations Planning Course in Portsmouth, England; the Operational Law Course at the JAG School, Charlottesville, Virginia, USA; the Law of Armed Conflict Course at the Institute for Humanitarian Law at San Remo, Italy; the Advanced Law of War Course, Liverpool University, England; and the Joint Operations Legal Training Course. 


COL Lambert is also the President of Army Cricket. Some of the highlights of his involvement with military cricket have included being a member of the Australian Army cricket team, the Australian Combined Services cricket team, the UK Adjutant General’s cricket team that toured Barbados in 2003, and as a member of the Australian Army cricket team that toured Pakistan in 2015 and 2016.


He also enjoys Muay Thai kickboxing, guitar and cycling. He is married to Jo and they have one child Sam.


In 2018 COL Lambert was posted to the role of Deputy Director of the Asia Pacific Centre for Military Law and Director of the Military Law Centre.