ManTech announced that it has named David Hathaway as Executive Vice President of the company’s Defense Sector. Reporting to Chief Operating Officer Matt Tait, Hathaway will lead strategic and operational initiatives delivering innovative technology solutions that support the critical missions of the company’s Department of Defense customers. Hathaway succeeds Andrew Twomey who has led ManTech’s Defense Sector since January 2015. Twomey is taking on a new strategic role within ManTech. Hathaway joins ManTech following a 25-year tenure at IBM in Public Sector executive leadership where he was charged with the development and delivery of advanced solutions for military and intelligence customers. Hathaway joins ManTech following a 25-year tenure at IBM in Public Sector executive leadership where he was charged with the development and delivery of advanced solutions for military and intelligence customers. He also served as Senior Vice President of Programs at Vectrus Systems Corporation in support of the Department of Defense and Intelligence Community.