"He was a great father, a great teacher, a great man and my hero," Patrick Bryne said of his father.
Overstock.com Co-President Stormy Simon said a portion of John Byrne's legacy and mentorship lives on within Overstock.
"It isn't just the financial investment with the stock he purchased," she said. "It's the personal investment by being chairman, mentor and sharing his years of business knowledge that will continue to contribute to our success."
For his part, Buffett had praise for Byrne in a letter to Berkshire shareholders, reviewing investments in 1980. He credited Byrne's "managerial brilliance" with resuscitating Geico after his arrival in 1976.
"There aren't many Jack Byrnes in the managerial world, or Geicos in the business world," Buffett wrote. "What could be better than buying into a partnership with both of them?"
At the time of the letter, Buffett's Berkshire Hathaway Inc. owned about one-third of Geico. Buffett bought the remaining two-thirds in 1996 for $2.3 billion and made it a unit of Berkshire. By then, Byrne had left Geico for White Mountains Insurance Group Ltd.
"Jack's performance in reviving Geico from near-bankruptcy was truly extraordinary, and his work resulted in enormous gains for Berkshire," Buffett wrote in his letter summarizing 1985, noting Byrne's departure. "We owe him a great deal for that."
Byrne's tough-love tenure at Geico entered the annals of corporate turnarounds.
He arrived in 1976 as president and chairman of Geico an acronym for Government Employees Insurance Co. after working as executive vice president at the Travelers Corp. Geico was near bankruptcy, having posted a net loss of $126 million in 1975, according to a 1981 article in Forbes magazine.
Byrne closed about 100 offices, cut the workforce to 4,000 from 7,000, quit the highly regulated auto insurance markets of New Jersey and Massachusetts, and raised rates by as much as 40 percent, Forbes said. He also reached a re-insurance agreement with competitors, potentially saving the industry, and sold $75 million in preferred stock to restore the company's capital, Forbes said.
By 1980, the company was back to health, with $44 million in net operating income in the first nine months.
Buffett, who had bought his first Geico shares in 1951 as a business student at Columbia University in New York, was among the buyers of the preferred stock that was part of Byrne's rescue plan.
Buffett, attracted to Geico's depressed share price, had arranged to meet Byrne soon after he took over as CEO.
"We talked to maybe 2, 3 a.m.," Byrne said of the meeting, at the home of Washington Post publisher Katharine Graham, according to Roger Lowenstein's "Buffett: The Making of an American Capitalist" (1995). "He wanted to know the things I would do. What did I think of our ability to survive?"
When the business day dawned a few hours later, Buffett called his broker and bought 500,000 shares of Geico at 2 1/8 and left a standing order for shares in the "multimillions," Lowenstein wrote. At the Washington Post board meeting that drew him to town, Buffett announced, "I've just invested in something that might go under. I could lose the entire investment next week."
Instead, Geico's share price almost quadrupled within six months, to 8 1/8, and Buffett became the controlling investor over the next few years, Lowenstein wrote.
Byrne, with advice from Buffett, hired Louis Simpson as Geico's chief investment officer in 1979. Simpson rose to president and CEO of Geico's capital operations from 1993 until 2011 and was once identified by Buffett as a candidate to succeed him in an emergency to oversee all of Berkshire's investments.
John Joseph Byrne was born on July 11, 1932, in Paterson, N.J., to John J. Byrne and Winifred Mohr Byrne. As a teenager, he worked at his father's insurance agency, according to a death notice on the website of Rand-Wilson Funeral Home in Hanover, N.H.
He graduated from Rutgers University in New Jersey in 1954 and earned a graduate degree in mathematics from the University of Michigan. He began his career as an actuary at Lincoln National Life Insurance Co.
After Geico, Byrne led the Fireman's Fund Insurance Co. until its acquisition in 1991 by Allianz AG Holding of Germany, now Allianz SE. He retained control of the fund's holding company, which he renamed Fund American Enterprises Inc. Today it is White Mountains Insurance Group.
Byrne served on the Board of Overseers of the Tuck School of Business at Dartmouth College in Hanover, which his three sons John, Mark and Patrick attended, according to the death notice.
Besides his sons, Byrne's survivors include his wife, Dorothy; seven grandchildren; and his brother, James Byrne, according to the funeral home.