Kimsey was born in Washington D.C. in 1939 and grew up in Arlington, Virginia.
After being dismissed from Gonzaga College High School, he attended St. John's College High School, followed by Georgetown University for one term on an honors scholarship, and then the United States Military Academy at West Point, from which he graduated in 1962.
Kimsey served in the U.S. Army, becoming a lieutenant and seeing active participation in U.S. interventions in the Dominican Republic and Vietnam. He served three combat tours as an Airborne Ranger, two in the Vietnam War, earning various awards for service and valor.
In July 2005, Kimsey was inducted into the Ranger Hall of Fame, which recognizes the United States' most extraordinary Rangers. In 2008, he received the Distinguished Graduate Award for Outstanding Service to the Nation from the U.S. Military Academy at West Point.
In 1970, after eight years in the military, Kimsey bought a building in downtown Washington, D.C., renting out the top floor. On the ground floor he built and opened a bar known as The Exchange. He "became successful and opened other bars in the 1970s." In May 1983, Kimsey became a manufacturing consultant for Control Video Corporation, which was near bankruptcy. He was brought in by his West Point friend Frank Caufield, an investor in the company.
CVC was founded by William von Meister to market an online service called GameLine for the Atari 2600 video game console. Von Meister had previously hired Steve Case as a marketing consultant on the recommendation of Case's brother, investment banker Dan Case. Von Meister quietly left the company in early 1985.
Shortly thereafter Control Video was reorganized as Quantum Computer Services, with co-founders Kimsey (CEO), Marc Seriff (CTO) and Steve Case. Quantum Computer Services was later reorganized as AOL. Kimsey served as CEO until 1995, when Steve Case took the helm. Kimsey was a key investor in, and a director of private military contracting firm Triple Canopy, Inc.
He also served as Chairman Emeritus of Refugees International, an independent advocacy group that works to protect refugees and end the cause of displacement. Kimsey also served as a member of the board of the Vietnam Veterans Memorial Fund and as a Senior Fellow to the Department of Defense Business Board.
He was a member of the James Madison Council of the Library of Congress. In 2010, Speaker Nancy Pelosi appointed Kimsey to the Library of Congress Trust Fund Board, which oversees the investment of all gifts for the benefit of the Library’s collection and services. He served on the Executive Committee of the National Symphony Orchestra.
His philanthropy also included the Kimsey Athletic Center at West Point, which he established in 1995.
Kimsey received numerous entrepreneurship awards. He received Presidential appointments to the Kennedy Center Board of Trustees and the West Point Board of Visitors. In 2001, Secretary of State Colin Powell named Mr. Kimsey as Chairman of the International Commission on Missing Persons, an organization dedicated to identifying hundreds of thousands of missing from conflicts and natural disasters around the world, through DNA research.
Kimsey died in McLean, Virginia of cancer on March 1, 2016, aged 76. Kimsey had three sons and four grandchildren.Kimsey resided in McLean, Virginia and had three grown sons: Mike, Mark and Ray.
In 1995 Kimsey established the Kimsey Foundation. His philanthropy includes the Kimsey Athletic Center at West Point.
In 2000, Kimsey purchased Marden House, designed by Frank Lloyd Wright, for $2.5 million.
In 2001, Kimsey was named Chairman of the International Commission on Missing Persons (ICMP) in Bosnia.
In 2005, Kimsey met with Generals John Abizaid and Wayne Downing regarding the Iraq war.
On October 30, 2006, Kimsey was appointed to the Board of Trustees of the John F. Kennedy Center for the Performing Arts by President George W. Bush.