O'Leary developed an interest in medicine, and cancer in particular, when her uncle died from lung cancer during her childhood. After graduating from University College Cork, she spent over ten years training and working at the Cork University Hospital. She currently works as a consultant gastroenterologist and general physician at South Tipperary General Hospital. She is also a patron of the Cork University Hospital Charity.
Mountaineering and adventure
O'Leary made her name in mountaineering in 2004, when she became the first Irish woman to reach the summit of Mount Everest, having failed on her first attempt in 2003 due to gastroenteritis. She climbed as a member of the Wyeth Irish Everest Expedition, led by Pat Falvey. She also became the first Irish woman to ascend the Himalayan peak Ama Dablam and to climb the Seven Summits—the highest mountains on each continent. In 2008, O'Leary joined the Beyond Endurance expedition led by Falvey to the South Pole, making her the first woman to successfully ski to the South Pole.
In 2012, O'Leary and Mike O'Shea set out on an ongoing series of expeditions that they called the Ice Project; their aim is to cross all of the world's largest ice caps. Some of these expeditions included crossings of the Northern Patagonian Ice Field, the Greenland ice sheet, and Lake Baikal. In 2014, they plan to attempt to ski to the North Pole after their 2012 North Pole trek was cancelled due to a logistics problem; this attempt will be O'Leary's fourth and O'Shea's second. They hope to be the first Irish people to reach the North Pole. A successful trip to the North Pole would also make O'Leary the second woman to climb the Seven Summits and reach both poles.
In November 2018, Clare was awarded an honorary doctorate by NUI Galway.
- "Climbing Everest... it's just what the doctor ordered". Evening Herald. 6 June 2013. Retrieved 19 March 2014.
- Cahill, Niamh (15 March 2013). "Challenges in testing times". Irish Medical News. Retrieved 19 March 2014.
- "Irish woman reaches the summit of Everest". Castlebar.ie. 18 May 2004. Archived from the original on 19 March 2014. Retrieved 19 March 2014.
- O'Sullivan, Majella (15 January 2014). "North Pole the goal for Irish adventurers". Irish Independent. Retrieved 19 March 2014.
- "Irish adventurers prepare for North Pole". The Irish Times. 13 February 2014. Retrieved 19 March 2014.
- "Dr Clare O'Leary completes 540km Siberian trek". The Southern Star. Archived from the original on 19 March 2014. Retrieved 19 March 2014.
- McMahon, Leo. "Bandon-Innishannon railway path to be named Dr Clare O'Leary Walk". The Southern Star. Retrieved 19 March 2014.
- McMahon, Leo. "Railway walk to Bandon named in honour of Dr Clare O'Leary". The Southern Star. Retrieved 19 March 2014.