Lieutenant General Bellon was commissioned as a Second Lieutenant in 1989. Bellon began service as an Infantry Officer with 2nd Battalion, 7th Marine Regiment. He then served as a Judge Advocate with 1st Force Service Support Group.

In 1997, he left active duty and joined the Selected Marine Corps Reserve serving six years with 4th Light Armored Reconnaissance (LAR) Battalion in a variety of positions. After 9/11, he returned to active duty for four combat tours in support of both OPERATION IRAQI FREEDOM (OIF) and OPERATION ENDURING FREEDOM (OEF). During OIF I, he served as Operations Officer for 4th LAR with both TASK FORCE TARAWA and TASK FORCE SCORPION. During OIF II, Bellon served as the Intelligence Officer for Regimental Combat Team 1 during its 14 month deployment in and around the City of Al Fallujah, Iraq, participating in both battles for the city. His third OIF tour was in Command of Battalion Task Force 3d Battalion, 23d Marine Regiment, in 2007-2008. The Task Force executed counter-insurgency operations in and around the city of Al Haditha, Iraq.

Bellon deployed to Afghanistan in September 2009 with the British 6th Division. While in Afghanistan, he served as the Chief of Operations for Southern Afghanistan during NATO's 2010 surge of forces to secure the strategically vital area in and around Kandahar City.

Bellon was promoted to Brigadier General in 2013. His assignments as a General Officer prior to his current billet include Deputy Commander (Mobilization) 1st Marine Expeditionary Force; Deputy Marine Forces Command; Director Reserve Affairs; Commander Marine Forces South; and Director of Strategy, Policy, and Plans (J5) U.S. Southern Command. He was promoted to his current rank and assumed duties as Commander, Marine Forces Reserve and Marine Forces North on 4 September 2019.