Warrant Officer Class One David Lehr was born in Wollongong, New South Wales on 1 November 1964, was educated at The Illawarra Grammar School and matriculated in 1982. He enlisted into the Australian Regular Army and commenced Recruit Training on 19 January 1983 and was allocated to the Royal Regiment of Australian Artillery as a Gun Number, Driver, Operator Command Post (Field) and Battery Commander’s Assistant at 4th Field Regiment, 1st Field Regiment and on exchange to ‘G’ Battery, 7th Parachute Regiment, Royal Horse Artillery.

Warrant Officer Lehr instructor appointments include Junior Leader Training Centre–Brisbane in 1991–92, and Regimental Training Wing, School of Artillery, North Head, in 1996. Warrant Officer Lehr was then posted to the Combined Arms Training Centre, Puckapunyal, when the School of Artillery relocated in 1997–98.

Warrant Officer Lehr was promoted to Warrant Officer Class Two in 1998 and took-up the appointment as Sergeant-Major Instructor Gunnery of 11th Field Battery, 23rd Field Regiment, in 1999. He was posted to ‘A’ Field Battery, Holsworthy, as the Battery Guide in 2002 and deployed on Operation TANAGER with the 3rd Parachute Battalion Group, The Royal Australian Regiment to East Timor. Warrant Officer Lehr returned to 4th Field Regiment in 2003 and took-up the appointment as Battery Sergeant-Major, 107th Field Battery. He was posted to Defence Force Recruiting Centre–North Queensland as a Defence Interviewer in January 2005.

Warrant Officer Lehr was promoted to Warrant Officer Class One in December 2005 and was appointment as Regimental Sergeant-Major of 2nd/10th Field Regiment in January 2006. He was appointed as Regimental Sergeant-Major of Combined Task Force 635 and deployed on Operation ANODE to the Solomon Islands with the 4th Brigade in 2007. He was then appointed as the Regimental Sergeant-Major of 1st Field Regiment from January 2008 to December 2010. He graduated from the Australian Command and Staff College and deployed on Operation SLIPPER to Afghanistan in 2011. He then took-up the appointment of Regimental Sergeant-Major Ceremonial-Army in February 2012.

Aside from Australian operational service and campaign medals, Warrant Officer Lehr has been awarded the Defence Force Service Medal with 3rd Clasp, the United States of America–Meritorious Service Medal and the Medal of the Order of Australia. He has also been presented the Army Combat Badge and was awarded the Commander, 2nd Division Commendation.

Warrant Officer Lehr has played a number of team sports that include cricket and rugby league. He has also represented the Australian Army playing rugby union and touch football. His interests are golf, surfing, military history, Australian muscle cars and Harley-Davidson motor cycles. 

Warrant Officer Lehr is married to Janelle who is also a full-time serving member in the Royal Australian Army Pay Corps and they have six children with one son a member of The Royal Australian Regiment.