Walter Maynard Ferguson was born on May 4, 1928, in Verdun, now part of Montréal, Québec. His parents started him on piano and violin at four, and at nine he asked for a cornet after hearing one in his local church. At thirteen he soloed with the Canadian Broadcasting Corporation Orchestra, and he was heard often on CBC radio, where Morris Davis wrote a "Serenade for Trumpet in Jazz" for him. He studied at the Conservatoire de musique du Québec à Montréal from 1943 to 1948 with Bernard Baker, left high school at fifteen, and worked in Montréal dance bands led by Stan Wood, Roland David and Johnny Holmes before taking over the band of his saxophonist brother Percy. In 1948 he moved to the United States hoping to join Stan Kenton, whose band had by then folded, and played instead with Boyd Raeburn, Jimmy Dorsey and Charlie Barnet. His feature on Barnet's "All the Things You Are" was pulled from sale after Jerome Kern's widow objected to it.

When Kenton formed his 40-piece Innovations Orchestra in January 1950, Ferguson was free to attend the first rehearsal, and one of the orchestra's pieces was named "Maynard Ferguson." He stayed when Kenton returned to a 19-piece jazz band, taking the third trumpet chair and a run of features including "What's New?", "The Hot Canary" and "Invention for Guitar and Trumpet." Readers of DownBeat voted him best trumpeter in 1950, 1951 and 1952. He left Kenton in 1953 and spent three years as principal trumpet at Paramount Pictures, appearing on 46 film soundtracks including The Ten Commandments. The contract kept him out of jazz clubs, so he recorded jazz dates under names such as "Tiger Brown" and "Foxy Corby." His studio years also put him in Los Angeles sessions led by Pete Rugolo, Shorty Rogers and Russ Garcia, and on the August 1954 Hollywood date that produced Dinah Jams with Dinah Washington, Clifford Brown and Clark Terry.

He left Paramount in 1956, recorded Havana 3 A.M. with the Pérez Prado orchestra that February and March, and joined the Birdland Dream Band, a 14-piece all-star group assembled by Morris Levy to play his Birdland club in New York. The name lasted for only two albums, but the band became the core of Ferguson's own orchestra, which AllMusic dates from 1957 to 1965. Recording mostly for Roulette, it was a proving ground for arrangers and soloists including Slide Hampton, Don Sebesky, Jaki Byard, Wayne Shorter, Joe Zawinul, Don Ellis, Bill Chase, Don Menza, Willie Maiden, Lanny Morgan and Joe Farrell. The studio album A Message from Newport, recorded in May 1958, took its title from the band's appearance at that year's Newport Jazz Festival, and in 1959 Ferguson was a guest soloist with the New York Philharmonic under Leonard Bernstein in William Russo's Symphony No. 2 in C, "Titans." In 1961 he wrote the theme for the ABC adventure series Straightaway. As big-band work dried up in the 1960s he fronted a sextet and shut the orchestra down in 1966.

From November 1963 he and his wife Flo lived for about three years on the Millbrook, New York estate where Timothy Leary and Ram Dass had gathered a community, and in 1967 he moved his family to India, where he taught at the Krishnamurti-founded Rishi Valley School near Madras and founded a boys' brass band at the Sri Sathya Sai Institute of Higher Learning. As a Canadian he was not covered by the British musicians' union ban on American players, so in 1969 he settled at Oakley Green, near Windsor, signed with CBS Records and built a 16- to 18-piece British band that played jazz-rock. Its version of Jim Webb's "MacArthur Park," on M.F. Horn (1970), became a concert staple, and the band made its North American debut in 1971.

Ferguson returned to the United States in 1973, later settled in Ojai, California, replaced the British players with young Americans recruited from college jazz programs at Berklee, North Texas State and the University of Miami, and built an audience through school concerts and clinics. From 1975 he worked with producer Bob James on large studio projects with strings, vocalists and guest soloists, beginning with Primal Scream (1976), which featured Chick Corea and Steve Gadd. The next album, Conquistador (recorded October to December 1976), included his version of "Gonna Fly Now" from Rocky. The single reached number 28 on the Billboard Hot 100 in June 1977, the album rose to number 22 on the pop album chart and became his only gold record, and he earned a Grammy nomination for best pop instrumental performance. In 1976 he also played a solo trumpet piece at the Summer Olympics in Montréal. His Columbia contract ended after Hollywood (1982), produced by bassist Stanley Clarke, and he made three big-band albums for smaller labels before forming the fusion septet High Voltage in 1986 with multi-reed player Denis DiBlasio.

For his 60th birthday in 1988 Ferguson went back to a larger band and a more mainstream jazz repertoire, which led to Big Bop Nouveau, a nine-piece group with two trumpets, trombone, three reeds and rhythm section that became his touring band for the rest of his career. It recorded for Concord Records through the 1990s, including These Cats Can Swing!, One More Trip to Birdland and Brass Attitude, and backed singers Michael Feinstein on Big City Rhythms (1999) and Diane Schuur on Swingin' for Schuur (2001). In 2005 the band toured for eight months at about 200 shows a year. Ferguson passed away on August 23, 2006, at Community Memorial Hospital in Ventura, California, of kidney and liver failure, after living in Ojai since 1973.

His honors include the DownBeat Hall of Fame (1992), the Canadian Music Hall of Fame (1997), the Prix Oscar-Peterson of the Montréal International Jazz Festival (1999), an honorary doctorate from Rowan University in New Jersey (2000), where the Maynard Ferguson Institute of Jazz Studies was founded in his name, and appointment as a Member of the Order of Canada (2003).

Ferguson was not the first trumpeter to work in the extreme upper register (Cat Anderson had done so), but he combined a screaming top range with a full, powerful tone, and he credited the control to breath work he discovered as a boy in Montréal and to the yoga and spiritual study he pursued in India. AllMusic's Scott Yanow writes that when he arrived in Stan Kenton's orchestra in 1950 he could play higher than any trumpeter before him, and that he stayed accurate. He doubled on valve trombone, flugelhorn and baritone horn, and designed the Firebird trumpet and the Superbone, a trombone with additional valves played with the left hand. His bands, from the Roulette-era orchestra to Big Bop Nouveau, gave many young players their first national exposure, among them Jaki Byard, Wayne Shorter, Joe Zawinul, Don Sebesky and drummer Peter Erskine. His 1970s Columbia albums, with their rock and pop covers, brought a young audience to big-band music and a gold record, though jazz critics, Yanow among them, found much of that material tasteless and preferred the Roulette recordings of 1958 to 1962 and the later Big Bop Nouveau sets.