Daniel O’Day is the Chairman and CEO of Gilead, the biopharmaceutical company which has more than 14,000 employees around the world. Gilead has developed innovative medicines that entirely alter the way diseases like HIV and viral hepatitis are treated and helped simplify medical care for people with life-threatening illnesses around the world. Prior to joining Gilead in March 2019, O’Day served as the CEO of Roche Pharmaceuticals. His career at Roche spanned three decades.

O’Day, who was the keynote speaker at Irish America’s Health Care / Life Sciences 50 dinner in 2017, was born in Texas and is a third-generation Irish-American with family from Ennis, County Clare, on his father’s side. “The perseverance of my Irish ancestors is a daily motivation to me professionally and personally,” O’Day says. His first job was landscaping, which, he says, “inspired me to pursue my education.”

O’Day holds a bachelor’s degree in biology from Georgetown University and an MBA from Columbia University in New York. He and his wife, Mara, have three children, Tierney, Meghan, and Brendan.