A native of Edison, N.J., Rear Adm. (select) Neagley graduated from the University of New Hampshire in 1982 and received his commission from Officer Candidate School in 1984. He holds a Master of Science degree in Financial Management from the Naval Post Graduate School and a Master of Arts degree in National Security and Strategic Studies from the Naval Command and Staff College.

Neagley has served at sea in USS Whipple (FF 1062), USS Coral Sea (CV 43), USS John Paul Jones (DDG 53), and as executive officer in USS Antietam (CG 54), where he deployed to the Arabian Gulf and participated in Operation Desert Fox with the Carl Vinson Battle group. He, subsequently, served as chief staff officer, Destroyer Squadron 21 and deployed with the Sea Combat Commander to the Arabian Gulf with the John C. Stennis Battle Group. He assumed command of USS Fitzgerald (DDG 62) in 2001 and led her combat deployment to the Arabian Gulf in support of Operations Iraqi Freedom and Enduring Freedom in 2003.

Ashore, Neagley was assigned as Research and Development, Test and Evaluation (RDTEN), and Weapons Procurement (WPN) appropriations manager, Surface Warfare Directorate (OPNAV N86) from 1996 until 1997. He reported to Future Ships Branch (OPNAV N763) in 2003 and served as the lead requirements officer for the Littoral Combat Ship (LCS) Program. In 2005, Neagley reported to the LCS Program Office as the principal assistant program manager and director of sustainment. From 2009 to 2011, Neagley served as the program manager of PMS EOD/CREW (PMS 408), where he fielded Explosive Ordnance Disposal (EOD) and counter Improvised Explosive Device (IED) systems to Iraq and Afghanistan. He was selected as the executive assistant to Naval Sea Systems Command in June 2011 and reported as the LCS program manager in March 2012. In September 2012, Neagley assumed duties as Space and Naval Warfare Systems Command deputy commander, Fleet Readiness.