First Warrant Officer Mohammad Haswandi bin Haji Paun was born on 20th September 1978. He was enlisted in the Royal Brunei Armed Forces (RBAF) on 8th April 1996 and underwent six months of recruit training. On 2nd January 1997, he was assigned as a Rifleman at A Company, First Battalion, Royal Brunei Land Forces (1Bn RBLF). 

Throughout his career, First Warrant Officer Mohammad Haswandi attended various courses such as 2IC Section Commander course on 28th July 1998 leading to his promotion to Lance Corporal. In the following year, he attended GPMG Commander Course in April 2000 and Infantry Small Arm Coaching in March 2003 at School Infantry Weapon in Singapore, Section Commander Course on 5th July 2002 as well as Weapon Coaching and Instructor Course on 18th February 2005, Drill instructor on 12th February 2004. He was later promoted to Corporal on 12th October 2001. 

First Warrant Officer Mohammad Haswandi also attended Platoon Sergeant Course and began his career as Platoon Sergeant in B Company, 1Bn RBLF before being promoted to Sergeant on 1st October 2008. He also attended Range Management Course and Company Sergeant Mejar Course at School of Infantry RBLF. He served as an Instructor at the Recruit company, Training Institute RBAF from 2006 to 2010. He promoted to Staff Sergeant on 16th August 2013 and was appointed as Company Quarter Master B Company, 1Bn RBLF. 

In 2014, First Warrant Officer Mohammad Haswandi was selected as a member of the Malaysian Battalion (850-12) to serve in the United Nations Interim Force in Lebanon (UNIFIL), where he held the role of Troop Sergeant. He was promoted to Warrant Officer 2 on 22nd June 2017 and since then had been appointed as the Company Sergeant Major for B Company, D Company, and Command Company, 1Bn RBLF. On 1st December 2020, he was appointed as Drill Sergeant Major at 1Bn RBLF. In December 2021, after being promoted to Warrant Officer 1, he was appointed Regiment Sergeant Major of the 1st Battalion RBLF for a two-year term. On 4th November 2023, he was appointed as the Field Sergeant Major at Field Headquarters, RBLF, and is set to assume the position of Land Forces Sergeant Major on 3rd February 2025.

First Warrant Officer Mohammad Haswandi was awarded General Service Medal (GSM) in 1997, RBAF Golden Jubilee Medal in 2011, United Nations Peacekeeping Medal in 2015, Pahlawan Periwara (PP) in 2018  and The Most Blessed Order of Setia Negara Brunei (PSB) in 2023 .

He is married with three children and enjoys playing golf and hiking.