Aldwin served in the British Army for twenty two years, predominantly as an officer in the Special Air Service (SAS), which he commanded in the early 1990s. During his time in Special Forces he saw operational service in many parts of the world, including the Falklands conflict; for his service there he was awarded the Military Cross. He later devised and oversaw UK military anti-narcotics policy for support to the government of Colombia. As the SAS Commanding officer he was responsible for the Regiment on its first ever deployment in support of the UN – the opening up of the Muslim pockets in Bosnia in 1994. He received the OBE in 1995.
Away from Special Forces, he served as Chief of Staff of Britain’s only airborne brigade, and was both a student and an instructor at the Army Staff College. He held a number of other high profile staff appointments, including Deputy Chief of Staff Special Forces during the Gulf War, Military Assistant to the General Officer Commanding Northern Ireland and Colonel Planning Staff – a post responsible to the Commanders-in-Chief for all the UK’s military contingency plans.
After leaving the British Army in 1997, Aldwin commanded the Sultan of Oman´s Special Force as an Omani Brigadier. He devised and implemented a five-year plan, which achieved a complete regeneration of the two thousand man force. He was present on the National Security Council of Oman for all security and counter-terrorist issues. As such, his understanding of Middle-Eastern affairs is profound. He was awarded the Military Order of Oman in 2001.