Dr. Irish is a Professor of Otolaryngology – Head and Neck Surgery and the Head of the Head and Neck Oncology and Reconstructive Surgery Division at the University of Toronto. He is a head and neck surgical oncologist and reconstructive surgeon with particular expertise and interest in oral cancer, melanoma and skin cancer, thyroid cancer as well as salivary gland tumors and malignancies.

Dr. Irish served as the Chief of the Department of Surgical Oncology at the Princess Margaret Cancer Centre from 2000 to 2016. Since 2004, he has been a major health policy advisor and responsible for access to care, quality improvement, and health care funding for the Surgical Oncology Program at Cancer Care Ontario. In 2004, he became the Clinical Lead for Access to Care and Strategic Funding Initiatives for the Surgical Oncology Program at Cancer Care Ontario and is responsible for the Cancer Surgery Wait Times portfolio. He was the Provincial Clinical Lead for Access to Services and Wait Times for the province of Ontario from 2008-2012. In 2008, Dr. Irish was appointed as the Provincial Head of the Surgical Oncology Program at Cancer Care Ontario where he has provided leadership and oversight linking volume funding to quality improvement. In 2019, Dr Irish was appointed Vice President, Clinical, Cancer Care Ontario at Ontario Health.

In his capacity as Vice-President, Clinical at Ontario Health-Cancer Care Ontario Dr Irish oversees the cancer care system for 15 million people in the Province of Ontario. In 2023, he was also appointed as the Chair of Clinical Council for Ontario Health.

As the Kevin and Sandra Sullivan Chair in Surgical Oncology at the University of Toronto, Dr. Irish leads a multidisciplinary program in Guided Therapeutics at UHN and is currently leads the Guided Therapeutics (GTx) Laboratory. Dr Irish is a Senior Scientist in the Princess Margaret Research Institute in the Cancer Biology and Imaging Program. In that capacity, he leads a multidisciplinary team of surgeons, engineers, physicists, and nanoparticle biochemists in the development of novel nanomedicine-based contrast agents, which, in combination with near real-time navigation and tracking systems, can create innovative solutions for minimal-access surgical approaches in cancer therapy. He has peer-review funding totaling over $10M with support from the Terry Fox Research Institute, the Canadian Cancer Society, CIHR and OICR.

Dr Irish has over 500 peer review publications and over 30 book chapters which represent other research interests in population-based outcomes, health services research and health policy implementation.