Dr. Justin Losier

Over the years, I’ve seen patients come in worried about injuries, illness, or the impact of lifestyle on their health — and leave feeling reassured, empowered, and ready to take control of their wellbeing. That’s the part of this work I love most.

I’m trained as both an adult and pediatric emergency physician and work as a family doctor, currently at Markham Stouffville Hospital and the Hospital for Sick Children. My passion for sports medicine and point-of-care ultrasound comes from extensive training across Ontario at the Universities of Ottawa, Western, Queen’s, and Toronto, and I take pride in combining that expertise with a personal, patient-centered approach.

When I’m not in the hospital, you’ll usually find me skiing or snowboarding, chasing waves on Lake Ontario with winter lake surfing, or finding new ways to stay active and challenge myself. Movement and adventure have always been a big part of my life, and they inspire how I approach patient care — helping people stay active, recover safely, and feel confident in their bodies.

Whether it’s guiding families through pediatric care, supporting athletes recovering from injuries, or helping someone navigate a new health challenge, my goal is always the same: to provide care that is knowledgeable, compassionate, and empowering, so patients can get back to the activities and life they love.