Teaching From 1986 – 1998, May taught in Staffordshire, West Sussex and Buckinghamshire, eventually becoming Headteacher of Manor Farm School in High Wycombe.

Business in the Community May left teaching in 1998 to become the Director of Education and Community Campaigns at Business in the Community, where he ran Partners in Leadership, a mentoring programme for headteachers in partnership with the National College of School Leadership; Time to Read, a national scheme to encourage employee volunteers to support literacy in primary schools; and commissioned the work to create the educational charity Teach First, becoming one of its founding directors and trustees.

The charity partners with schools and colleges to offer a structured program of mentoring, masterclasses, workplace visits, and internships.

The charity's efforts focus on empowering young individuals from diverse backgrounds to achieve their full potential and make a positive impact on their communities and the economy.

He was responsible for overseeing the implementation and expansion of the Award across more than 130 countries, ensuring its principles and standards were upheld worldwide – and oversaw a growth in global participation from 750,000 to more than 1.3 million.

During the global COVID pandemic he worked with the United Nations and the World Health Organization to create opportunities for young Award participants to contribute to their communities.

As Chief Executive, May has led the charity’s strategic planning and governance, helping the organisation to enhance its services and advocacy efforts for the well-being of cats across the country.

In this role, May was instrumental in modernising the organization's approach to international youth engagement, focusing on inclusivity, diversity, and preparing young people with essential life skills.

His contributions extended internationally through his work with the World Organization of the Scout Movement (WOSM), promoting global citizenship and cross-cultural understanding.

By supporting the Sea Cadets, May has helped provide young people with opportunities to develop nautical skills, leadership qualities, and a sense of discipline and community service.

In addition, High Sheriffs actively lend support and encouragement to crime prevention agencies, the emergency services and to the voluntary sector.