Simon Kay studied medicine at Oxford University. He trained in the UK, Australia and USA. He specialised in children’s hand surgery as a consultant plastic surgeon in Leeds in 1987, later becoming Professor of Hand Surgery at the University of Leeds. He is active nationally and internationally. He continues to teach, innovate and publish.

He developed a multidisciplinary hand surgery service in Leeds, and a children's hand surgery service that is now the largest such clinic in the UK. He pioneered microsurgery in reconstruction of children's hands and has been a foremost advocate for the integration of clinical psychology into the surgical care of children and their families.

He has researched and published in children’s hand reconstruction, brachial plexus surgery in adults and children, and nerve repair. He co-edited the world’s major textbook in children’s hand surgery The Growing Hand, and is the Editor in Chief of the Oxford Textbook of Plastic Surgery.

He conceived and led the European Instructional Courses in Hand Surgery. These courses are still the premier educational instrument in Hand Surgery in Europe.

Kay was Editor of The Journal of Plastic Reconstructive and Aesthetic Surgery (2002 – 2007), President of The British Society for Surgery of the Hand (2007), and President of the British Association of Plastic Reconstructive and Aesthetic Surgeons (2009). He was Editor in Chief of Journal of Brachial Plexus and Peripheral Nerve Injury (2010 - 2012).

He led the team that undertook the first UK Hand Transplant, in 2012, and subsequently succeeding in obtaining central funding for Leeds as the designated UK centre for Hand and Upper Limb Transplantation. The service in Leeds is amongst the most active in the world.