McGuire began his coaching career as an assistant at
Dartmouth College (1955–1957) for head coach
Doggie Julian. McGuire coached the freshman team at Dartmouth. One of his players was
Dave Gavitt. McGuire then took his first head coaching job at
Belmont Abbey College (1957–1964), in Belmont, North Carolina, where he recruited many high school players off the streets of New York. McGuire became head coach at
Marquette University in
Milwaukee in 1964 where he enjoyed success, including the
NIT Championship in
1970 and a
Final Four appearance in
1974 against the eventual champion
NC State Wolfpack. He also served as athletic director for the program starting in 1973. His final assistant coaches were
Hank Raymonds (hired in 1961) and
Rick Majerus (hired in 1971), who became a successful college head coach. He cited them as the final key to the team's success in 1977, stating, "We worked because we didn't associate socially and our rhythms were different. Hank was the encyclopedia, the administrator, the rule book with solid basketball knowledge. Rick was the cousins sandwich, the guy to bridge the age gap with the players, the recruiter with a flair for modern-day basketball. I was the Houdini, who did his disappearing act. I know that 85 percent of me is buffalo chips, and the other 15 percent is rare talent. I'd say in that 15 percent, in the mental toughness, the media, keeping an eye on the elephant, not the mice, and extending the life of the extinct kiwi bird, which is nocturnal." McGuire led Marquette to its only NCAA basketball championship in
1977, his final season as a head coach. On December 17, 1976, McGuire stunned fans by announcing that he would retire as coach after the end of the
current season, to become vice chairman of Medalist Industries, effective May 1, 1977; he had served on the board of directors of the sporting goods firm for six years. North Carolina coach and friend
Dean Smith had stated that McGuire never intended to be a "lifer" as a coach. McGuire was an executive with the company for less than a year, resigning on March 20, 1978. For the entire tournament, McGuire would wear a black sport coat and gray pants that he believed was lucky. Marquette's team, led by
Alfred "Butch" Lee,
Maurice "Bo" Ellis and
Jerome Whitehead would have a run that Maguire later referred to as "the magical weekend", which saw Whitehead receive a full-court pass and subsequently made a last-second shot to propel Marquette past
UNC Charlotte in the national semifinals. Two days later, they defeated
Dean Smith's
North Carolina Tar Heels for the title. Ranked sixteenth, Marquette had seven losses going into the NCAA tournament, the most losses up to that time for a team that would win the NCAA Championship. The thrilling weekend in Atlanta's
Omni Coliseum provided a happy sendoff. McGuire was succeeded by his assistant
Hank Raymonds, who in turn was succeeded by Majerus in 1983; Marquette would not reach another Final Four until 2003. While at Marquette, McGuire founded "Al's Run," a charity event for the
Children's Hospital of Wisconsin. The race celebrated its 40th anniversary in 2017. ==Broadcasting career==