Assaf Hakimi grew up in Jerusalem and came to the bass late by conservatory standards. He picked up the electric bass at 17 and did not add the upright until he was 22, after military service. In January 2001 he moved to New York, and the seven years that followed did the work a childhood start usually does. In 2002 the jazz program at the New School gave him a scholarship for outstanding performance and ability, and he was chosen to represent the school in its jazz outreach program. His teachers there were a roll call of working New York musicians: pianist Junior Mance, bassist Reginald Workman, saxophonists Jane Ira Bloom and Billy Harper, bassists Doug Weiss and Johannes Weidenmueller, pianist Hal Galper, and trumpeter Jimmy Owens.

He worked steadily around the city through the decade, in the clubs and on the bandstands of players including clarinetist Paquito D'Rivera, drummer Billy Hart, pianist Aaron Goldberg, and trombonist Wycliffe Gordon. In February 2009, with his return to Israel already decided, he booked a session at Michael Brorby's Acoustic Recording in Brooklyn and made Some Other Day, the album that closed out his New York years. He assembled a quintet of Israeli expatriates plus one American: Eli Degibri on saxophone, Jonathan Voltzok on trombone, Alon Yavnai on piano, and Clarence Penn on drums. Hakimi wrote seven of the nine pieces; the other two are Duke Ellington's "Prelude to a Kiss" and the standard "So Near, So Far." Reviewing it for All About Jazz in March 2010, Eyal Hareuveni described gently melodic hard-bop writing with arrangements built to give every player room, and called Hakimi an assured leader well versed in the bop tradition.

He moved back to Israel in April 2009 and dropped straight into the Tel Aviv scene, which turned out to suit a bassist with no strong preference about idiom. Within a year he was in the Albert Beger Electroacoustic Band, a free-jazz group whose Peacemaker was cut live at Anova Music Studios in Tel Aviv over two days in July 2010 with Albert Beger on saxophones, Ido Bukelman on guitar, Avi Elbaz on laptop and electronics, and Dani Benedikt on drums. He was on Bukelman's own free-improvisation record Ido Bukelman's Cracked Song the following year, and on Ofer Peled's Ararat and Harel Shachal's Hasipur, both of which run jazz through Middle Eastern instrumentation. He also anchored two sextet dates for drummer Roy Oliel and recorded Italian-Jewish liturgical repertoire with the singer Charlette Shulamit Ottolenghi.

The most visible credit of that period came in 2014, when John Zorn handed volume 23 of his Book of Angels series to the Cuban-American drummer Roberto Juan Rodriguez. Hakimi played double and electric bass on the resulting Aguares (Tzadik TZ 8322), a record that puts Zorn's Masada compositions through Afro-Cuban rhythm alongside pianist Omri Mor, clarinetist Gilad Harel, and a full percussion section. That same year he was the bassist on singer Daphna Levy's Late Night Journey, a mainstream date that brought in Lew Tabackin on tenor saxophone.

Since then Hakimi has become one of the bassists Israeli leaders call for a straight-ahead record. He plays acoustic and electric bass on saxophonist Alon Farber's Reflecting on Freedom (Origin Records, 2021), recorded in August 2020, and he is the bassist in ZurHub, the Brazilian-jazz quintet founded in 2017 by flutist Mattan Klein and guitarist Ezequiel "Hezi" Jait, whose Countryside Motorways came out on Origin in August 2025. He teaches at conservatories and music programs around Tel Aviv, and he has built a leader project of his own that has never been recorded: the Assaf Hakimi Sextet, an ensemble fronted by four saxophones over just bass and drums, playing his originals and standards arranged for that front line. It has been on stage since at least 2020 and played the Red Sea Jazz Festival's Winter Edition in Eilat on February 23, 2023.

Hakimi's own writing sits squarely in hard bop. The compositions on Some Other Day are built on clear melodic heads and thematic narratives rather than on vamps or textures, and he scores them for a horn-heavy front line that leaves the bass to hold the structure, which is where he seems to want it. What separates him from other bassists in that tradition is the range of what he has been willing to sit in on since returning to Israel: a free-improvisation guitar record, a live electroacoustic set with laptop electronics, klezmer-Cuban hybrids for Tzadik, Italian synagogue melodies, Brazilian jazz, and conventional saxophone-quintet dates, all inside fifteen years. That breadth is a working Israeli bassist's normal life rather than a stylistic statement, but it has produced a discography with unusually little repetition in it. His scoring instinct shows most clearly in the sextet he leads now, which strips out piano and guitar entirely and asks four saxophones to supply all the harmony over his bass line.