[2] Shortly after his mother's death in 1927, he entered Manlius Military School in Onondaga County, New York.

[5] In 1940, McIntyre was admitted to the bar and joined the law office of former Senator Robert W. Upton in Concord.

[1] He was then assigned to the 94th Infantry Division and later served in the Third Army under General George S. Patton, participating in all the major European campaigns.

[3] At the end of the war, he was made a military government judge of the Amtsgericht (lower court) in Düsseldorf, Germany.

[1] Following his military service, McIntyre returned to Laconia and joined the law office of Harold E. Westcott in 1946.

[3] He also joined his brother as a partner in McIntyre Properties, a firm that owned and managed rental real estate, and served as president of the Community TV Corporation, which specialized in television antennae.

[2] In 1954, McIntyre won the Democratic nomination for the United States House of Representatives from New Hampshire's 1st congressional district.

During the campaign, McIntyre ran on a platform supporting President John F. Kennedy's proposal for federal aid to education and for medical care to the elderly under Social Security.

[12] McIntyre led an unsuccessful attempt to filibuster George H. W. Bush's confirmation as Director of Central Intelligence in 1976, believing the former chairman of the Republican National Committee would politicize the agency.

[5] In 1978, he was narrowly defeated for re-election to a fourth term by Gordon Humphrey, who took advantage of a nationwide conservative movement and McIntyre's tendency to spend more time in Florida than in New Hampshire.

Recognizing the rising power of the New Right in his defeat, McIntyre published The Fear Brokers, in 1979, co-authored with John Obert.