John Leahy joined JSM in April 2021, bringing an outstanding track record of value creation in private equity that is directly relevant to JSM’s growth journey. He has extensive experience scaling businesses organically and through buy-and-build strategies, upgrading capabilities and operations across multiple sectors.

As Chairman, John provides strategic guidance across finance, business development and operations. He served as Operating Partner at Doughty Hanson for 18 years and has deep expertise in renewable energy, including 12 years as Chairman of LM Windpower and his current role at GEV Windpower.

Michael Booth joined JSM in February 2025 as Chief Financial Officer before being appointed Chief Executive Officer in September 2025.

An accomplished executive, Michael brings extensive expertise in financial reporting, audit, compliance, treasury management and change management. He has successfully led major acquisitions, divestments and ERP transformation programmes, combining a strategic outlook with a continuous improvement mindset. Known for building strong relationships across teams, Michael is focused on driving sustainable growth and operational efficiency, bringing both the financial rigour and leadership presence that JSM needs at this exciting stage of its development.

As co-founder and Chief Operations Officer, John Scanlon is responsible for the implementation of JSM’s strategy and the operational performance of the business. With decades of industry experience, John brings in-depth knowledge of programming, planning and monitoring work programmes, delivering proactive solutions to complex engineering challenges with safety and quality at the forefront. He provides the strategic direction to the operations that underpin the entire JSM service offering.

John is passionate about developing people from within, a commitment reflected in the establishment of the JSM Training Centre.

Helen Stewart joined JSM in January 2025, bringing more than 20 years of global HR leadership experience and a chartered professional qualification.

A transformation specialist with diverse sector expertise, Helen is skilled at translating people strategy into tangible commercial outcomes. In her role, she is responsible for building an engaged workforce, strengthening organisational capability and shaping a future-ready culture that supports JSM’s growth ambitions. Helen combines strategic thinking with a practical, human-centred approach, ensuring that JSM’s people are equipped, motivated and ready for what comes next.

David Rough leads JSM’s Power business, overseeing the design, construction and maintenance of electricity networks for transmission and distribution operators.

With over 30 years of electricity industry experience, Dave began his career as an apprentice before rising to Senior Manager level at London Electricity (now UK Power Networks), working on landmark projects including Canary Wharf and King’s Cross. He leads a highly skilled team delivering electrical engineering, project management and commercial expertise in a specialist market. Dave is driven by a genuine commitment to customer service, quality and safety in every project JSM delivers.

Daniel Rowan is a seasoned leader in telecoms infrastructure with over two decades of experience driving innovation and operational excellence across major fibre and connectivity programmes.

Previously Operations Director for Openreach FTTP and Ethernet Services at OCU, Daniel scaled annual turnover from £360k to over £40 million through strategic leadership and customer-focused delivery. He has managed nationwide fibre rollout projects and connected critical infrastructure across research, telecoms and education sectors. Known for his hands-on style and commitment to health, safety and quality, Daniel is passionate about empowering high-performance teams to deliver outstanding results.