Fergus McCreadie was born on July 12, 1997, in Jamestown, Easter Ross, in the Scottish Highlands, and grew up in Dollar, Clackmannanshire. His first instrument was the bagpipes, which he has said he was not good at. At about twelve he saw a jazz piano performance that, in his words, changed his life, and his parents bought a broken-down piano for twenty pounds. After a neighbor complained about the noise, he did most of his practicing on a Yamaha electric piano through headphones in his bedroom.

He attended Dollar Academy, won the under-17 category of the Young Scottish Jazz Musician of the Year competition in 2013 and 2014, and was runner-up in the main competition in 2015. In 2016 he won the Peter Whittingham Jazz Award. At the Royal Conservatoire of Scotland he studied jazz piano with Tommy Smith and played in Smith's youth jazz orchestra, and it was there that he met the bassist David Bowden and the drummer Stephen Henderson, who became the other two thirds of his trio. He graduated in 2018, the year he was a finalist in the BBC Jazz Musician of the Year competition. The trio's self-released debut, Turas (December 2018), won album honors at the 2019 Scottish and Parliamentary Jazz Awards and was shortlisted for the 2019 Scottish Album of the Year Award.

McCreadie signed to Edition Records, the label run by Dave Stapleton, in May 2020. The trio had recorded Cairn at QuietMoney Studios in Hastings on January 7 and 8, 2020, and Edition released it on January 29, 2021. All nine pieces are his own compositions, and the cover uses photographs of stones he collected in the Highlands. MOJO gave it five stars, and it was longlisted for the 2021 Scottish Album of the Year Award. The trio returned to QuietMoney on July 6 to 8, 2021, to make Forest Floor, released April 8, 2022. It was shortlisted for the 2022 Mercury Prize, won the Scottish Album of the Year Award in October 2022 and the Scottish Jazz Award for Best Album, and he was also named Instrumentalist of the Year at the 2022 Jazz FM Awards. In 2022 he was selected for BBC Radio 3's New Generation Artists scheme, the only non-classical musician chosen that year.

A solo piano EP, Sketches, followed on November 26, 2023, recorded on August 21 at Solas Sound in Glasgow. The fourth trio album, Stream (May 3, 2024), was made with BBC Radio 3 and built around water, running from dark to lighter material across its length; Stream (Revisited), a five-track EP of reworked pieces including a version of "The Teacher" from Turas, came out on April 4, 2025. In August 2025 the trio contributed music to the soundtrack of Spike Lee's film Highest 2 Lowest, released both within the film's soundtrack and as a separate trio EP on A24 Music. The fifth album, The Shieling, was released on October 24, 2025. Produced by Laura Jurd, it was recorded over several days in January in a remote cottage at Lochmaddy on North Uist in the Outer Hebrides, with the trio playing in one room around an upright piano. A companion EP of further pieces from the sessions, The Shieling - Companion Pieces, appeared on July 17, 2026.

Outside his own trio, McCreadie has played piano on albums by Graham Costello's Strata, by the saxophonist Matt Carmichael, by Esther Swift and Siobhan Miller, and on the 2026 corto.alto album Some Small Fortune. As of 2022 he lived in Glasgow.

McCreadie writes for a piano trio and draws on the landscape and folk music of Scotland: place names, hill walks, rivers and weather supply his titles and much of his material, and he has described jazz as "kind of a folk music in itself." MOJO's five-star review of Cairn praised the trio's energy and originality and compared them to The Bad Plus and E.S.T., and a 2024 concert review in The Skinny noted the contrast between his plain-spoken stories about mountain streams and Scottish weather and the hypnotic music itself. He names Keith Jarrett as the pianist who inspired him most, and has also cited Brad Mehldau and Pat Metheny, along with Oscar Peterson, McCoy Tyner, the classical pianists Glenn Gould and Martha Argerich, and the Irish traditional musicians Caoimhín Ó Raghallaigh and Mick O'Brien. Forest Floor reached the top of the UK jazz and blues chart. Ethno Jazz is the closest tag available for this blend of contemporary piano-trio jazz and Scottish folk music.