James Day was raised in the northwest Oklahoma community of Pond Creek and graduated from Enid High School before earning his B. S. Degree in Business Administration from Phillips University. He spent forty-four years in the energy sector—fourteen years at ONEOK and thirty years at Noble Corporation. As chairman of the board, chief executive officer, and president of Noble Corporation, founded in 1921, Day and his team helped build one of the largest worldwide offshore drilling companies. Over his tenure, the market capitalization grew 15,000% and the company became a member of the Standard & Poor's 500 and Fortune 500.

Day has served, or is currently serving, on a number of public company's board of directors, including EOG Resources, Inc., Noble Energy, Inc., Tidewater, Inc., Global Industries, the Independent Petroleum Association of America, the Society of Petroleum Engineers, and is a member of the Mewbourne College of Earth and Energy Board of Visitors at the University of Oklahoma. He is an honorary board member of the American Petroleum Institute, where he previously served on the Policy Committee and as chairman of the General Membership Committee.

In 2007, Day established the James C. and Teresa K. Day Foundation with a focus on education. Through the foundation and personally, he has been a strong supporter of many Oklahoma endeavors and entities, including the Cherokee Strip Regional Heritage Center, National Cowboy & Western Heritage Museum, Oklahoma Historical Society, Oklahoma History Center, Oklahoma Foundation for Excellence, Charles B. Goddard Center for Visual and Performing Arts, Inc., Arcadia Trails, Pond Creek-Hunter High School, and the University of Oklahoma. Day also served as co-chair for the 125th Live On University Campaign for the University of Oklahoma.