John McLaughlin was born on January 4, 1942, in Doncaster, South Yorkshire, England, into a family of musicians. His mother, Mary, was a concert violinist and his father, also named John, an engineer of Irish descent; the couple separated when he was seven, and he was raised mostly by his mother and grandmother. He studied violin and piano as a child, and at eleven his brother gave him a guitar. He took to it at once, working through flamenco, the swing of Django Reinhardt and Stéphane Grappelli, and the modern jazz of Tal Farlow and Jim Hall, with John Coltrane, Bill Evans and Thelonious Monk among the musicians he later named as models. In the early 1960s he moved to London and lived largely on session work, playing in the groups of Alexis Korner, Georgie Fame and Brian Auger, and in 1963 he joined the Graham Bond Quartet with bassist Jack Bruce and drummer Ginger Baker. Bond also introduced him to Indian culture and philosophy, an interest that ran through everything he did afterward. He gave guitar lessons to a young Jimmy Page and spent part of 1968 around the free-jazz scene of the German vibraphonist Gunter Hampel. His first album as a leader, Extrapolation, was recorded at Advision Studios in London in January 1969 with saxophonist John Surman, bassist Brian Odgers and drummer Tony Oxley, and was released by Marmalade later that year.

Early in 1969 McLaughlin moved to New York to join drummer Tony Williams's group Lifetime, with organist Larry Young, and the band recorded Emergency! that year. He had been in the United States for less than two weeks when Miles Davis asked him to a recording session, and he went on to play on In a Silent Way, Bitches Brew (which includes a short piece titled for him), A Tribute to Jack Johnson, Live-Evil, Big Fun (where he is the featured soloist on "Go Ahead John") and On the Corner. In the same period he played on albums by Wayne Shorter (Super Nova), Miroslav Vitous, Larry Coryell, Joe Farrell and Carla Bley, and made two records of his own for Douglas: Devotion (1970), a loud, psychedelic set with Young and the drummer Buddy Miles, and the acoustic My Goal's Beyond (1971), with bassist Charlie Haden, drummer Billy Cobham, saxophonist David Liebman and the tabla player Badal Roy. He became a follower of the Indian spiritual teacher Sri Chinmoy in 1970, took the name Mahavishnu, and dedicated that second album to Chinmoy.

In 1971 he formed the Mahavishnu Orchestra in New York with Cobham, keyboardist Jan Hammer, violinist Jerry Goodman and bassist Rick Laird. After a week of rehearsal the band opened for John Lee Hooker at the Gaslight at the Au Go Go and entered the studio soon afterward; The Inner Mounting Flame (recorded in August 1971) and Birds of Fire (1973, which reached No. 15 on the Billboard 200) became defining records of jazz-rock, built on odd meters, Indian-inflected scales and very high volume. Disputes over leadership and songwriting credit, and a strained session at Trident Studios in London in June 1973, ended the group after its last concert on December 30, 1973; McLaughlin dissolved it the following month, and the Trident recordings did not appear until 1999 as The Lost Trident Sessions. In 1973 he also recorded Love Devotion Surrender with Carlos Santana, who was also then a Chinmoy disciple, an album that includes two Coltrane pieces. He rebuilt the orchestra in 1974 with violinist Jean-Luc Ponty, keyboardist Gayle Moran, bassist Ralphe Armstrong and drummer Narada Michael Walden. That band recorded Apocalypse (1974) with the London Symphony Orchestra, conducted by Michael Tilson Thomas and produced by George Martin, then Visions of the Emerald Beyond (1975) and the quartet album Inner Worlds (1976), and by then McLaughlin had broken with Chinmoy.

In 1974 he also helped found Shakti, an acoustic group built on Indian classical forms, with the violinist L. Shankar, the tabla player Zakir Hussain and the percussionist T. H. "Vikku" Vinayakram; they made three albums between 1975 and 1977, played Montreux in 1976 and 1977, and took over his working life once the orchestra ended. He returned to electric guitar for Electric Guitarist (1978), which drew on guests such as Chick Corea, Stanley Clarke, Jack DeJohnette, Tony Williams and Jack Bruce across its tracks. In 1979 he formed Trio of Doom with Williams and Jaco Pastorius, which played one concert, at the Havana Jam festival in Cuba on March 3, 1979, and recorded in New York days later (the tapes were released in 2007), and led the One Truth Band on Electric Dreams. With the flamenco guitarist Paco de Lucía and Al Di Meola he made Friday Night in San Francisco, recorded at the Warfield Theatre on December 5, 1980, followed by Passion, Grace & Fire (1983). In the 1980s he also led the Translators, a French and American band that included the pianist Katia Labèque (Belo Horizonte, 1981, and Music Spoken Here, 1982), revived the Mahavishnu name from 1984 to about 1987 with a Synclavier guitar system, played on Davis's You're Under Arrest (1985) and Aura, took part in the film 'Round Midnight (1986) with Dexter Gordon, and wrote the Mediterranean Concerto for guitar and orchestra, orchestrated by Michael Gibbs and recorded with Tilson Thomas and the London Symphony Orchestra. From the late 1980s he toured and recorded in a trio with the percussionist Trilok Gurtu (Live at the Royal Festival Hall, from November 27, 1989, and Qué Alegría, 1992), and he has lived in Monaco since that time.

The 1990s were split between acoustic and electric projects. Time Remembered (1993) was a tribute to pianist Bill Evans for acoustic guitars; the Free Spirits trio with organist Joey DeFrancesco and drummer Dennis Chambers recorded Tokyo Live (1994); After the Rain (1995) paired him with DeFrancesco and Elvin Jones; and The Promise (1995) brought in guests including Jeff Beck, Sting, Michael Brecker and David Sanborn. The guitar trio reunited for The Guitar Trio (1996), and the electric quintet album The Heart of Things (1997) featured Chambers and saxophonist Gary Thomas. In 1997 he and Hussain revived the Shakti idea as Remember Shakti, which later added the mandolinist U. Srinivas, the percussionist V. Selvaganesh and the singer Shankar Mahadevan; Saturday Night in Bombay (2001) was nominated for a Grammy. After Thieves and Poets (2003), a set of orchestral and chamber music and jazz standards, and Industrial Zen (2006), he left Verve for Abstract Logix in 2007 and formed the 4th Dimension, first with keyboardist and drummer Gary Husband, bassist Hadrien Féraud and drummer Mark Mondesir, later with bassist Etienne Mbappé and drummer Ranjit Barot. Floating Point (2008), made largely with Indian musicians, was Grammy-nominated, and a 2008 tour with Corea, drummer Vinnie Colaiuta, saxophonist Kenny Garrett and bassist Christian McBride as the Five Peace Band produced Five Peace Band Live, which won the 2010 Grammy for Best Jazz Instrumental Album.

The 4th Dimension made To the One (2010, Grammy-nominated), Now Here This (2012), Black Light (2015) and Live @ Ronnie Scott's (2017); his solo on "Miles Beyond" from the last of these won the 2018 Grammy for Best Improvised Jazz Solo. A late-2017 U.S. tour with the guitarist Jimmy Herring was billed as his farewell American tour. Is That So? (2020) teamed him with Mahadevan and Hussain, and Liberation Time (2021), written during the pandemic lockdowns, includes two solo piano pieces. Shakti reunited in 2020 with Hussain, Mahadevan, Selvaganesh and the new violinist Ganesh Rajagopalan; its album This Moment (2023), the first under that name in 46 years, won the 2024 Grammy for Best Global Music Album, and the group toured the world in 2023 for its fiftieth anniversary. Hussain died on December 15, 2024, and the live album drawn from that tour, Mind Explosion, appeared in July 2025 and received two nominations at the 2026 Grammys (Best Global Music Album and Best Global Music Performance); McLaughlin has called it the group's final record. DownBeat inducted him into its Hall of Fame in 2024, and Berklee College of Music gave him an honorary doctorate in 2017. In a DownBeat interview published in November 2024 he said that he had stopped touring after the 2023 Shakti tour, though he still played occasional charity concerts. His score for the film Abandoned Heights, released as Music for Abandoned Heights, appeared in 2025, and in September 2026 he joined Eric Clapton on stage at the Crossroads Guitar Festival.

McLaughlin's playing combines very fast alternate picking, the harmonic vocabulary of modern jazz, and scales and rhythmic cycles drawn from Indian music, which he studied for years, including the veena; he has been described as one of the first Westerners to play Indian music for Indian audiences. On the first Mahavishnu records he played a Gibson EDS-1275 double-neck guitar through a Marshall amplifier, a sound Guitar Player later placed among the fifty greatest guitar tones; for Shakti he used a custom Gibson J-200 built by Abraham Wechter with extra sympathetic strings under the main set, and from the late 1970s he added scalloped fingerboards, guitar synthesizers and, later, Godin and PRS instruments. His influences ran from Django Reinhardt, Tal Farlow and Jim Hall to John Coltrane, Charles Mingus (whose "Goodbye Pork Pie Hat" he recorded on My Goal's Beyond), the flamenco guitarist Sabicas and Jimi Hendrix. His fusion of jazz with rock, Indian classical music and flamenco shaped a generation of guitarists, among them Al Di Meola, Mike Stern, Steve Morse, Gary Moore, Eric Johnson and Scott Henderson, and Chick Corea said that the Mahavishnu Orchestra, more than his own time with Miles Davis, made him want to turn the volume up. Jeff Beck called him the best guitarist alive in 2010, and Pat Metheny has called him the world's greatest guitarist. The reaction was not uniform: Frank Zappa, who toured with the Mahavishnu Orchestra in 1973, admired the technique but was less taken with some of the lines, and Ritchie Blackmore dismissed him. Rolling Stone ranked him 49th in its 2003 list of the greatest guitarists, and he has won many DownBeat and Guitar Player poll awards.