In 1990 as 2nd Lieutenant of the Armed Forces he completed the Commissioning Course at Royal Military Academy Sandhurst in the United Kingdom, where he was awarded the "Oman prize" for academic achievement.

[1] Serving as a lieutenant in 1991/92, Xuereb commanded a platoon and in 1993 was appointed as Staff Officer III Personnel within Headquarters.

[1] A colonel as of 2 November 2007, Xuereb was subsequently appointed as deputy commander of the Armed Forces of Malta on 9 January 2008.

Xuereb temporarily returned to the United Kingdom between January and December 2009, where he was a member of the Royal College of Defence Studies.

[3] Since 2014, Xuereb has been Director of the Migrant Offshore Aid Station, a humanitarian, non-profit project aimed at assisting vessels in distress in the central Mediterranean.