Mimecast, a global cybersecurity leader, has appointed Leslie Nielsen as its new Chief Information Security Officer (CISO). Nielsen, a 25-year cybersecurity veteran, comes to Mimecast from Klaviyo, a high-growth marketing automation platform. He has previously served as SVP and CISO at Klaviyo, contributing to the company’s $1.3B revenue, security function, and IPO readiness, ensuring the organization is well-positioned for public markets.
“We sought out a leader who can see beyond the noise and hype to deliver an innovative security platform, and Leslie fit the bill perfectly,” said Mimecast CEO Marc van Zadelhoff. “I’m excited to welcome him to the Mimecast team and for his expertise in scaling world-class security at a time when cyber defense is at its most critical. Leslie’s proven experience leading security teams will be invaluable to safeguarding our customers and hardening our resilience strategy.”
As CISO, Nielsen will spearhead Mimecast’s global cybersecurity strategy, driving the company’s threat intelligence, risk assessment, and incident response initiatives, as well as ensuring regulatory compliance, reinforcing Mimecast’s commitment to providing the highest levels of protection for its more than 42,000 global customers.
“I’m thrilled to join Mimecast on their mission to secure the human layer in the new age of AI-powered security threats,” said Nielsen. “The industry is at a pivotal point where defense strategies must place humans at the center, and Mimecast has long been at the forefront of the human side of security. I look forward to building on the company’s strong foundation and helping shape its next chapter of innovation and resilience.”
Before Klaviyo, Nielsen held SVP and CISO roles at Nuance Communications, SAP Concur, and SuccessFactors, the CTO role at SOS Security, and senior roles at IBM and ACS (acquired by Xerox). He was also a member of Google’s CISO Cloud Advisory Board. He earned his Bachelor of Science in Computer Science from Texas Tech University.
