AI legal tech firm Definely has named Sigurjón Ísaksson, the company’s head of AI, as its new chief technology officer.
A former machine learning engineer at Samsung, Ísaksson has held a number of prominent roles across tech startups, including co-founding the family-oriented fintech Nosso.
The automation specialist was hired by Definely, known for its generative legal document drafting and reviewing tools, as its head of AI in 2024. In that time the company saw a period of significant growth, notably securing a £22m Series B investment in June of last year.
As CTO, Ísaksson will lead the company’s product development and support the scaling of its technical department, overseeing plans to invest in new AI engineers to continue the business’s growth.
“2025 has shown that Definely’s AI offering is uniquely positioned within a crowded market, and the customer success speaks for itself,” Ísaksson said.
“I have spent the last two years developing first-of-its-kind AI solutions for complex contract reviewing, unifying Definely’s existing product stack to solve end-to-end workflows for lawyers, and I look forward to doubling down on this as CTO. I am excited to lead an incredible tech team and push the boundaries of deep AI innovation we have achieved in 2025. ”
Definely has been backed by a number of prominent investors, including Octopus Ventures and Cornerstone VC.
“Sjonni has already proven what he can do at Definely. As Head of AI, he led the development and launch of Enhance and Cascade, products now trusted by law firms and in-house legal teams around the world,” commented Definely chief executive Nnamdi Emelifeonwu.
“Appointing him as CTO gives us continuity and real momentum: faster shipping, stronger technical ownership across both AI and platform, and a clear focus on scaling reliability, security, and enterprise readiness as demand accelerates.
“Just as importantly, Sjonni is building the kind of high-performing engineering organisation that will help us deliver consistently as we grow.”
