John, a Catalyst founder, has been involved in the information technology industry throughout his professional career and has taken technical, managerial, marketing, and financial roles in markets that include computational physics, defence and aerospace, commercial information systems, and software engineering. He has lived and worked both in Europe and in the USA.

Before the founding of Catalyst in 1996, he established the US operations of a UK-based company specializing in IT mergers and acquisitions, and was responsible for many of the company's transatlantic and North American advisory assignments and transactions. He began his professional career at Rolls-Royce in computational physics. At London-based Scicon Ltd (now HP), John then played roles ranging from project and financial management, to international marketing, including leading the company's expansion into the US defence market. John subsequently launched the US operations for Jackson Systems, a major software tools development firm.

John is the chairman of The Portable Office Company Ltd (POC), and of Observant Technology Ltd. He has also served as non-executive Chairman and as a non-executive director of AIM listed Universe Group PLC.