Major General Neller was commissioned a Second Lieutenant via the Platoon Leaders Class program in May 1975. After completing The Basic School in April 1976, he was assigned to Lima 3/4, 3d Marine Division where he served as a rifle and weapons platoon leader and as company commander. Returning to CONUS in June 1977, he was assigned to MCRD San Diego where he served as a recruit series officer, aide-de-camp and as Director of Special Training Division. In January 1980, he was promoted to Captain and in May 1980 transferred to Camp Pendleton and 1st Marine Division where he participated in the ARMVAL Test as an evaluation observer and HQ Section OIC. Upon conclusion of ARMVAL, he served 19 months as Commanding Officer of Alpha Company 1/1 and deployed to Okinawa as part of the Unit Deployment Program. From Oct 82 to May 83 he attended the Advanced Armor Officer Course at Ft. Knox where after graduation he was assigned to The Basic School, where he served as a Student Company Executive Officer and as a tactics instructor.

Promoted to Major June 1, 1986, he was transferred to Headquarters Marine Corps for duty with the Special Projects Directorate. In July 1988 he was ordered to Panama as Commanding Officer, Marine Corps Security Force Company, Panama. During this tour he participated in Operations "Just Cause" and "Promote Liberty". Returning to Quantico in the summer of 1990, he attended the Marine Command and Staff College and upon graduation was ordered back to 1st Marine Division where he was assigned as Commanding Officer, 3d Light Armored Infantry Battalion. Promoted to Lieutenant Colonel in August of 1992, he deployed with 3d LAI to Somalia from December 92 to February 1993 as part of Operation "Restore Hope". After giving up command of 3d LAI in June of 1993, he was assigned as Executive Officer of the 7th Marines until January 1994 when he left 29 Palms, California to attend the NATO Defense College in Rome, Italy.

Upon completion of TLS in July of 1994, he spent the next 3 years on the staff of the Supreme Headquarters Allied Powers Europe (SHAPE) in Casteau, Belgium as a staff officer in the Policy Division. During this period he attended the Armed Forces Staff College and deployed to Bosnia-Herzegovina as a member of the Stabilization Force (SFOR).

Selected for Colonel in the spring of 1997, he was assigned to II Marine Expeditionary Force (MEF) at Camp Lejeune in August 1997 and was subsequently assigned as the II MEF G-3. He was promoted to Colonel on 1 October 1997. In July 1998 he was re-assigned as the Commanding Officer of the 6th Marine Regiment and served with 6th Marines until July 2000. Upon completion of his command assignment, he served as the 2d Marine Division G-3. Colonel Neller was selected for Brigadier General in March 2001. He assumed duties as the Assistant Division Commander of 2d Marine Division during June of 2001. In July 2002 he was assigned to Headquarters, U.S. Marine Corps as the Director, Operations Division, Plans, Policies (PP&O), and in September of 2005, was re-assigned as the Deputy Commanding General (Operations), I Marine Expeditionary Force (Forward), Camp Pendleton and subsequently deployed to Iraq in support of Operation Iraqi Freedom 05-07 from February 2006 to February 2007. In January 2007 he was promoted to Major General. He subsequently served as the Assistant Division Commander for 1st Marine Division. Major General Neller assumed command of 3d Marine Division in June of 2007.