Major General Roberts' regimental postings culminated with command of the 1st Field Regiment at Enoggera in 1991 and 1992.  The focus of the Regiment during his tenure as the Commanding Officer was introduction of the Ready Reserve Scheme into the 6th Brigade and the 1st Field Regiment.

As a colonel, Major General Roberts served as Director Weapons and Vehicle Procurement in Materiel Division-Army,  and Director Military Strategy and Director-General Military Strategy in Headquarters Australian Defence Force.  In 1997 he was promoted to the rank of brigadier to command the 7th Task Force at Enoggera, Brisbane.  He then went on to command the Peace Monitoring Group in Bougainville from late 1999 to early 2000, and the Combined Arms Training and Development Centre in Puckapunyal for the remainder of 2000.

. 

Major General Roberts was promoted to the rank of major general and appointed to command the Army’s Training Command in 2001.  He was appointed Deputy Chief of the Army in mid-2002 and Head of Defence’s Strategic Policy Division in mid-2004.   

Major General Roberts attended the Royal School of Artillery and the Royal Military College of Science, both in the UK, the Australian Army Command and Staff College and the Australian College of Defence and Strategic Studies.  He holds a Bachelor’s Degree in Civil Engineering, a Master of Science Degree in Gun Systems Design and a Graduate Diploma in Management Studies

Major General Roberts was appointed a Member of the Order of Australia in 2001 and an Officer of the Order in 2004 in recognition of his service in senior Army command and staff appointments.

Major General Roberts left the Army in 2005 to join the Senior Executive Service of the Australian Public Service.