Just 43 when he was appointed the 13th defense secretary during the Ford administration, now at 70 he is considered an experienced and valuable part of President Bush's foreign policy team.
He takes a hard-line approach to defense issues, lobbying to boost the defense budget to $379 billion (an increase of $48 billion from last year) and to modernize the nation's defense program. He was responsible for the reorganization of the worldwide structure Unified Command Plan, which resulted in the establishment of the U.S. Northern Command and the U.S. Strategic Command.
He is also a leading spokesman for the war on terrorism -- a fight he says includes launching a pre-emptive U.S. military strike in Iraq and overthrowing Iraqi president Saddam Hussein. His was the public face of the war in Afghanistan and in overthrowing the Taliban and will likely remain so as the U.S. embarks upon a war with Iraq.
Rumsfeld is known for his candor although that directness has sometimes ruffled feathers. A recent example is his charge in February that Germany and France -- key critics of a military intervention in Iraq -- were "old Europe" and not representative of a new way of thinking.
Although he has spent nearly two decades in the private sector, the secretary is considered by many to be a career politician. He was born in Chicago in July 1932 and graduated from Princeton University in 1954, the same year he married his high school sweetheart, Joyce. After graduation, he served a three-year stint in the U.S. Navy as an aviator and a flight instructor.
Rumsfeld first entered the political arena after his military service in 1957 when he served as a congressional administrative assistant.
He soon sought his own seat in Congress, running and winning the seat to represent the 13th district of Illinois in the U.S. House of Representatives in 1962. He was re-elected four times before he resigned in 1969 to join the Nixon administration. Under President Nixon, he was both an assistant and a counselor to the president, as well as Director of the Office of Economic Opportunity and Director of the Economic Stabilization Program.
In 1973, Rumsfeld became U.S. ambassador to the North Atlantic Treaty Organization (NATO), then returned a year later to the White House to head Gerald Ford's transition team before becoming the president's Chief of Staff.
Rumsfeld was confirmed as defense secretary in 1975, serving in the post for 14 months. During that time, he was a key proponent of several weapons systems, including the B-1 bomber, the Trident nuclear submarine program, and the MX missile.
After President Ford left office, Rumsfeld took a hiatus from politics, first lecturing at his alma mater and at Northwestern University's Kellogg Graduate School of Management. He later became a CEO for various companies, including a pharmaceutical group and an electronics firm.
Rumsfeld returned to Washington to become campaign chairman for presidential candidate Bob Dole in 1996 and later to chair the nine-member Ballistic Missile Threat Commission, which concluded that weapons programs in Iran and North Korea posed a greater threat to the U.S. than previously thought.
Rumsfeld is known for using a compilation of well-oiled aphorisms based on his past experiences to guide him. One of "Rumsfeld's Rules" is "The Secretary of Defense is not a super general or admiral. His task is to exercise civilian control over the Department for the Commander-in-Chief and the country."
-- By Raven Tyler, Online NewsHour