Toward the end of his second term, he narrowly captured the U.S. Senate seat of a retiring Jennings Randolph in 1984. He won by comfortable margins in each of his five terms.
Rockefeller hails from a family of many achievers: In addition to the successes of his oil billionaire great-grandfather, two uncles, Nelson Rockefeller and Winthrop Rockefeller, served as governors of New York and Arkansas, respectively. Rockefeller's father, John D. Rockefeller III, was a well-known philanthropist and founded the Asia Society, while his uncle David Rockefeller ran Chase Manhattan Bank.
"West Virginia has become my life and my cause," Rockefeller said. "I never, ever doubt what it is I'm trying to do. West Virginia provides that to me in the form of fantastically hard-working, tough, warm-hearted people."
Rockefeller became the state's senior senator upon the 2010 death of Robert C. Byrd, a fellow Democrat and history's longest-serving member of Congress. In his remaining time in office, he said, he plans to focus now on the fight over federal spending, taxes and the debt limit and the future of such programs as Medicaid.
"We have a whole lot of work to do for the next two years," Rockefeller said. "I'm very glad I'm going to be a part of that."
Rockefeller was to be joined during Friday's formal announcement by his wife, Sharon Percy Rockefeller, and other family members. The couple have four adult children and six grandchildren. Sharon Rockefeller was successfully treated for colorectal cancer after a 2005 diagnosis, and the senator has more recently endured torn tendons in his left knee.
"I will spend the next couple of years thinking of what I can do to continue to fight for the causes I believe in," Rockefeller said. He added, "I will not be leaving West Virginia. West Virginia will always be my home."