Professor Isabel Oliver has been appointed chief medical officer for Wales.
Leaving her role as director general of science and research and chief scientific officer at the UK Health Security Agency (UKHSA), she will replace Sir Dr Frank Atherton who stands down at the end of the month.
As chief medical officer for Wales, Professor Oliver will provide clinical leadership and be responsible for providing independent professional advice to the Welsh Government.
She will also be working with organisations across Wales to reduce health inequalities and lead the medical profession with the aim of improving the quality of healthcare and patient outcomes.
Professor Oliver began her career working in acute hospital medicine in the West Midlands and the South West of England, before moving into public health. Before working at the UKHSA, she was director of national infection service at Public Health England (PHE).
She also currently serves as co-director of the National Institute for Health Research, Health Protection Research Unit on Behavioural Science and Evaluation at the University of Bristol, and an honorary professor at University College, London.
Professor Oliver said: "It is an honour to be appointed as the Chief Medical Officer for Wales and I am very excited to work with the dedicated health professionals and the communities across Wales to create a Healthier Wales and safeguard our NHS.
"Today, we face challenges from our ageing population, inequalities and global factors such as climate change. For someone like me with a great passion for health and wellbeing, there are some unique opportunities in Wales to secure major improvements in public health and health services for all, thanks to innovative policies and effective collaboration between sectors and it will be my privilege to serve the people of Wales to secure healthy, resilient and prosperous communities."
On the appointment, cabinet secretary for health and social care, Jeremy Miles, said: "Professor Oliver brings a wealth of experience to Wales after working at a senior level in public health in the UK and I look forward to working with her.
"I’m delighted she has joined us as we work to improve health and wellbeing, and I’d like to offer her a warm welcome to Wales."