Ellwood graduated from Duntroon in 1990 and was commissioned into the Royal Australian Infantry Corps. His early career included postings as a platoon commander in the 2nd/4th Battalion, Royal Australian Regiment and as an instructor in field training and tactics at Duntroon, before he was seconded to the British Army from 1998 for a two-year exchange with the Irish Guards, then stationed in Germany. During the secondment he deployed as part of the NATO intervention in the Kosovo War in 1999, serving as second-in-command of an armoured infantry company in the King's Royal Hussars Battle Group.[1][4][5] For his service in Kosovo, Ellwood was awarded a Commander British Forces Commendation. He returned to Australia as a company commander and operations officer in the 5th/7th Battalion, Royal Australian Regiment (5/7RAR). Ellwood commanded B Company on operations in East Timor from October 1999 to April 2000, when 5/7RAR deployed with the International Force East Timor.[1][2][5][6]
Ellwood briefs defence minister Peter Dutton and US Army Colonel Matthew Dalton during Exercise Talisman Sabre at Camp Growl, Queensland, on 18 July 2021
Ellwood subsequently served as chief of staff Headquarters Forces Command and as Director General of Career Management – Army. Promoted to major general, he was appointed Deputy Chief of Army on 3 May 2018. He occupied the role for only seven months, before succeeding Major General Paul McLachlan in command of the 1st Division on 6 December 2018.[1][5] Ellwood was appointed a Member of the Order of Australia in the 2019 Queen's Birthday Honours, the award recognising his "remarkable capacity and exceptional leadership and management skills ... across a number of [senior] roles".[12]
Ellwood relinquished command of the 1st Division to Major General Scott Winter in November 2021 and,[13] for his "outstanding achievement" in the command, was awarded the Conspicuous Service Cross in the 2022 Australia Day Honours.[14][15] The following March, he was appointed State Recovery Coordinator by the Premier of Queensland to lead the large-scale recovery operations in response to the severe floods in South East Queensland.[16] Ellwood retired from the army in December 2022, and the following March was appointed Chief Executive Officer of the Queensland Reconstruction Authority.[17]
Ellwood is married to Nicole, with whom he has two children. He is patron of the 5RAR Association, and his interests include military history, scuba diving, long-distance running, and fishing.[1][5]
12"Distinguished Service Cross (DSC)"(PDF). Australia Day 2009 Honours. Office of the Governor-General of Australia. Archived from the original(PDF) on 12 September 2009. Retrieved 28 November 2019.
Blaxland, John (2008). "Near and Far: Operations, 1999–2006". In Horner, David; Bou, Jean (eds.). Duty First: A History of the Royal Australian Regiment (2nded.). Sydney: Allen & Unwin. pp.306–346. ISBN978-0-04-442227-3.
Horner, David; Bou, Jean, eds. (2008). "Appendix C: Commanding Officers". Duty First: A History of the Royal Australian Regiment (2nded.). Sydney: Allen & Unwin. pp.438–444. ISBN978-0-04-442227-3.