John N. Stewart is a prominent cybersecurity executive with over 35 years of experience in information security, threat intelligence, and global security operations. He began his career in the 1980s at the National Security Agency (NSA), where he held various technical and leadership roles focused on cryptography, network security, and counterintelligence, contributing to early developments in U.S. government cybersecurity practices. In 2000, Stewart transitioned to the private sector, joining Symantec Corporation as Vice President of the Security Response division, where he directed worldwide threat analysis, vulnerability research, and incident response teams, helping to establish Symantec as a leader in antivirus and security software. In 2005, he joined Cisco Systems as Chief Security Officer, later advancing to Senior Vice President of Security and Trust in 2015, a position he maintained until 2021. During his tenure at Cisco, he oversaw the company's global security strategy and operations, including product security, trust and compliance initiatives, and response to major cyber threats affecting enterprise networks. His leadership emphasized proactive defense mechanisms and collaboration with governments and industry partners. Following his departure from Cisco, Stewart has continued to influence the cybersecurity landscape through advisory roles, board positions, and speaking engagements at industry conferences, advocating for enhanced public-private partnerships in combating cyber risks.