Lesław Henryk Możdżer was born in Gdańsk on March 23, 1971, and was put in front of a piano at five at his parents' suggestion. The training that followed was entirely classical and it ran the full course: he took his diploma from the Stanisław Moniuszko Academy of Music in Gdańsk in 1996, from the instrumental faculty, in the piano class of Andrzej Artykiewicz. Jazz arrived late by the standards of the music, at eighteen, in his last year of school. His first working band was the clarinettist Emil Kowalski's, and the two were still recording together a decade later on Children of Bird (Jazz Art Collection, 1999), a programme of eight Charlie Parker tunes and one Irving Berlin, with Cezary Paciorek's accordion in place of a horn section.

What actually made his name was Miłość, the Tricity band at the centre of the Polish yass movement, which he joined in 1991 and stayed with until 2002. Miłość was a deliberate provocation aimed at the Polish jazz establishment, and the records are loud, funny and formally reckless in a way nothing else in his catalogue is: the self-titled debut cut at the Szczecin Radio studios in September 1992, Taniec Smoka in April 1994, and Asthmatic in 1996, where his credit reads piano and mezzo-soprano vocals. Twice the band brought in Lester Bowie, first for a live set at the Eskulap club during the Poznań Jazz Fair on November 19, 1994, released as Not Two, and then for the studio album Talkin' About Life and Death, taped at Polish Radio Gdańsk on July 9 and 10, 1997. In parallel he was doing the opposite kind of work: he took the piano chair on the Zbigniew Namysłowski Quartet's Secretly & Confidentially, recorded at Radio Olsztyn over eight days in December 1993, and on Tomasz Stańko's score for A Farewell to Maria, cut at Warsaw's S4 studio in June 1993. The competition results came in the same stretch, an honourable mention and a second prize with Miłość at Jazz Juniors in 1992, then first place at the International Jazz Improvisation Contest in Katowice in 1994.

His own catalogue opens with Chopin: impresje (Polonia Records, 1994), a solo recital of Chopin material with two guests dropped into it, Stańko's trumpet on one piece and Namysłowski's alto on another. The Chopin thread never went away, and neither did the film work: he has been a long-standing collaborator of the film composers Zbigniew Preisner and Jan A. P. Kaczmarek, playing the piano part on tracks 10 to 18 of Preisner's Requiem for My Friend (Erato, 1998) and on Kaczmarek's scores for Unfaithful (2002) and Finding Neverland (2004). The jazz records of those years are duo records: Facing the Wind with the American bassist David Friesen at Warsaw's Studio S-3 in April 1996, which includes a Wayne Shorter tune among Friesen's originals, and two concert albums with the saxophonist Adam Pierończyk, Live in Sofia (1998) and 19-9-1999, recorded in Vinnitsa, Ukraine, on the date its title gives. Chopin Tomorrow: Demain, Impressions was made in Paris in 1999 for Opus 111. He was named Jazz Musician of the Year at the Fryderyk awards in 1999 and given the Culture Ministry's Ad Astra prize in 2001.

2004 was the year everything opened up at once. The solo album Piano (ARMS Records) reached number 7 in Poland and went platinum, unusual placings for a jazz record on a national sales chart, and the Roma Theatre concert at which he was handed the gold disc for it became Piano Live. On September 25 he played the Weill Recital Hall at Carnegie Hall opposite the older Polish pianist Adam Makowicz; the duo record that came out of it, Makowicz vs. Możdżer at the Carnegie Hall, went platinum as well. And in July, at the eleventh International Jazz na Starówce festival in the Old Town Square in Warsaw, he put a band together for a single night. He took the Swedish bassist and cellist Lars Danielsson, and for the third chair, rather than a drummer, he hired the Israeli frame-drum player Zohar Fresco. The booking became permanent. Możdżer Danielsson Fresco has now made seven records over twenty years, and the first three sold on a scale no other Polish jazz group has matched: The Time (Outside Music, September 2005) was double platinum inside two months and was certified diamond in Poland in 2013 for sales past 50,000; Between Us and the Light (2006) and Polska (2013) are each double platinum. There is no drum kit on any of them.

The two decades since have alternated between the trio, a duo partnership with Danielsson that produced Pasodoble (ACT, 2007, cut at Nilento Studios in Gothenburg over the turn of 2006 and 2007) and the Danielsson-led Tarantella (2009), and a run of solo and crossover projects. Komeda (ACT, 2011), eight pieces by Krzysztof Komeda recorded on a Fazioli 212 at his own studio in Wrocław over four days in March 2011, went to number one on the Polish album chart and double platinum. Kaczmarek by Możdżer took the 2011 Fryderyk for best original soundtrack. In 2012 he became the first Pole to chair the jury of the Montreux Jazz Piano Competition, held under the patronage of Quincy Jones, and ACT issued The Last Set: Live at the A-Trane, a two-piano concert he had played in Berlin with the American Walter Norris on November 2, 2008, and which reached the shops a year after Norris's death. His opera Immanuel Kant, after the Thomas Bernhard play, had its world premiere at the Warsaw Chamber Opera on December 22, 2015 and was staged at the Wrocław Opera on November 25, 2017. Since 2011 he has been artistic director and co-creator of the Enter Enea Festival, held by Lake Strzeszyńskie in Poznań, whose sixteenth edition ran from May 31 to June 3, 2026. He was given the Knight's Cross of the Order of Polonia Restituta in 2013 and the Silver Gloria Artis medal in 2025, and Jazz Forum's critics' poll named him musician of the year, pianist of the year and composer of the year for 2024.

The tuning work is the strand that ties the recent records together, and it is not a gimmick he arrived at late. Earth Particles (2017), an album of his own compositions made with the Dutch period-instrument orchestra Holland Baroque, is performed throughout at A = 432 Hz. Beamo, the trio's twentieth-anniversary album, goes further: it was recorded at Monochrom Studio in Poland from September 18 to 22, 2023, with additional cello parts taped at Tia Dia Studios in Mölnlycke, Sweden, that December, and Możdżer plays three different grand pianos on it. A Fazioli in ordinary equal temperament at A = 440 Hz, a Steinway in equal temperament at A = 432 Hz, and an Östlind & Almquist tuned to A = 440 Hz but in a decaphonic scheme that divides the octave into ten equal steps rather than twelve. The instrument was built to his specification and is, as far as its makers and his label claim, the only decaphonic piano in existence. The record came out in Poland in November 2024 and internationally on ACT on March 28, 2025, with two piano tuners credited on the sleeve.

Możdżer is the rare jazz pianist whose classical conservatory training is audible in every bar without ever sounding like a costume. His label describes him as "the great romantic among European jazz pianists," and the compliment is precise: the technique is conspicuous, the phrasing is lyrical rather than motivic, and the tunes stay singable through improvisations that are harmonically far from where they started. The Chopin obsession is real and recurring, running from his 1994 debut through the Paris recital of 1999 that Opus 111 issued as Chopin Tomorrow and that Naïve later reissued, unchanged and under a new title, as the chart-placing Impressions on Chopin, and it sits alongside a similarly persistent engagement with Komeda, the other Polish pianist-composer whose language he has spent a career translating. Two other things mark him out. One is the drummerless trio: by giving the rhythm chair to Fresco's frame drums instead of a kit, he removed the ride cymbal from a European piano trio and forced the piano to carry more of the time itself, which is why those records do not sound like anyone else's. The other is his war on equal temperament, which he has called a pixelation of music into twelve compulsory tones, and which he has attacked in practice by recording at A = 432 Hz and by commissioning a piano tuned in ten equal divisions of the octave. Alongside the jazz sits an unusually wide non-jazz working life, film scores for Preisner and Kaczmarek, a comic opera, and guest piano for David Gilmour, Phil Manzanera and the death metal band Behemoth; it is the jazz that has defined him, but the traffic in both directions is a large part of why a jazz pianist sells platinum records in Poland.