Edgar Gómez was born on October 4, 1944, in Santurce, Puerto Rico, and moved with his family to New York while still an infant. His first musical footing was vocal rather than instrumental: his mother sang around the house, and on visits back to Puerto Rico he sang in English at his grandfather's evangelist church. A junior high school music teacher handed him a double bass at eleven, and at thirteen he entered the New York City High School of Music and Art, where he studied classical repertoire and jazz alongside classmates who included flutist Jeremy Steig, drummer Billy Cobham, and keyboardist Richard Tee. From fifteen he studied privately with Frederick Zimmermann, a New York Philharmonic bassist from 1930 to 1966 whose students also included Charles Mingus, Henry Grimes, and Red Mitchell, and whose expressive, singing conception of the instrument became the foundation of Gómez's own. Between 1959 and 1961 he played in the Newport Festival Youth Band under Marshall Brown, a group that also carried Eddie Daniels and Ronnie Cuber. At seventeen he met a twenty-year-old Juilliard student named Chick Corea at a jam session in Corea's Manhattan loft. On Zimmermann's recommendation he entered Juilliard himself in 1962, and his graduation is recorded as 1963.

He was a member of Local 802 while still a teenager, and the working life he built around his studies was unusually wide: a long engagement at a midtown steakhouse with pianist Marian McPartland, Latin dates, and downtown avant-garde sessions. Two of the latter put him on record at twenty. On October 20, 1964, at Studio 76 in New York, he played bass in Paul Bley's quintet on Barrage (ESP-Disk 1008), a program entirely of Carla Bley compositions with Marshall Allen on alto, Dewey Johnson on trumpet, and Milford Graves on drums. Weeks later, on November 11, 1964, at Bell Sound Studios, he recorded The Giuseppi Logan Quartet (ESP-Disk) with Logan, pianist Don Pullen, and Graves again, a record Elliott Sharp would later put on a list of ten essential free jazz albums. In 1965 he worked under vibraphonist and arranger Gary McFarland and saxophonist Gerry Mulligan, both of whom he has described as mentors.

The Mulligan association is what brought him to Bill Evans. In the summer of 1966 Gómez was working nights at the Copacabana behind Bobby Darin while also appearing at the Village Vanguard in Mulligan's group, opposite Evans's trio. Evans complimented him and said he hoped they would play together, then called a few weeks later with an offer of a West Coast tour. Gómez left the Darin job for it, and after a trial run that included Shelly's Manne-Hole in Los Angeles, Evans asked him to stay. He was twenty-one. His first studio session with the pianist was cut on October 4, 1966, his twenty-second birthday, at Rudy Van Gelder's studio in Englewood Cliffs, New Jersey: A Simple Matter of Conviction (Verve V6-6785), produced by Creed Taylor, with Shelly Manne on drums.

Gómez stayed eleven years, longer than any other bassist Evans employed, through a rotating cast of drummers: Manne in the studio, then Philly Joe Jones, then Jack DeJohnette, then Marty Morell from 1968 to 1974, then Eliot Zigmund. Two of those records brought Grammy Awards that Gómez shares as a member of the group. Bill Evans at the Montreux Jazz Festival, cut live at the Casino de Montreux on June 15, 1968 with DeJohnette, won the 1969 Grammy for Best Jazz Instrumental Album, Individual or Group. The Bill Evans Album (Columbia C 30855), recorded at CBS 30th Street Studio across five days in May and June 1971 with Morell, won two awards at the 1972 ceremony, one of them the group prize. In the gap after Morell's departure, Evans finally made a project he had wanted for years, a piano-and-bass duo record: Intuition (Fantasy F-9475), taped at Fantasy Studios in Berkeley on November 7 to 10, 1974, followed half a year later by the live Montreux III. The classical conductor George Cleve, who sat in on the Intuition sessions and wrote its liner notes, called Gómez one of the two greatest bassists in jazz history. The last Evans studio date Gómez played was You Must Believe in Spring, recorded at Capitol Studios in Los Angeles on August 23 to 25, 1977 and held back until February 1981, five months after Evans's death. Throughout the Evans decade Gómez also kept a parallel duo going with Jeremy Steig, documented on the live Outlaws (Enja 2098), recorded at Die Glocke in Bremen on December 15, 1976.

After 1977 he became one of the most in-demand bassists in New York, working duo engagements at Bradley's in Greenwich Village and taking on projects at both ends of the idiom. He played on Mingus's last two Atlantic records, Me, Myself and Eye (1979) and Something Like a Bird (1980), sessions Mingus composed and supervised but, disabled by ALS, did not play on. He toured and recorded with DeJohnette's New Directions band for ECM, with Corea on The Leprechaun (1976), The Mad Hatter (1978), Friends (1978), and Three Quartets (1981), and with Hank Jones's Great Jazz Trio, where he and Al Foster replaced Ron Carter and Tony Williams by 1980, with Jimmy Cobb taking the drum chair in 1982. In 1979 he was a founding member of Steps, the band that grew out of after-hours sessions at Seventh Avenue South, the club owned by Michael Brecker and Randy Brecker, with vibraphonist Mike Mainieri, Michael Brecker, pianist Don Grolnick, and drummer Steve Gadd. The group cut its first two albums in Tokyo within a single week, Step by Step on December 8 and 10, 1980 and Smokin' in the Pit live at the Pit Inn on December 14 to 16, both issued on Nippon Columbia's Better Days imprint. Renamed Steps Ahead, it moved to Elektra/Musician for Steps Ahead (1983) and Modern Times (1984). His session work in these years ran well past jazz, taking in Carly Simon's Torch, Art Garfunkel's Lefty, David Grisman's Hot Dawg, and the Kronos Quartet's Music of Bill Evans.

His own leader catalog began in Japan and largely stayed there for a decade. Down Stretch (Trio Records PA-7141) was recorded at AOI Studios in Tokyo on January 22 and 23, 1976 with pianist Takehiro Honda and Zigmund. Gomez (Interface YF-7089), taped at SEDIC Studios in Tokyo in January and February 1984 with Corea and Gadd, carries a dedication to Bill Evans and Frederick Zimmermann. Mezgo followed from CBS/Sony's Shinanomachi studio in November 1985 and was issued internationally as Discovery; Power Play (Columbia C 44214) and Street Smart came in 1988 and 1989. Next Future (Stretch GRS 00062, 1993) was co-produced by Gómez and Corea at Skyline Studios in New York. From the mid-1990s he led a working trio with pianist Stefan Karlsson and Jimmy Cobb, heard on Dedication (Evidence ECD 22208-2), recorded June 9 and 10, 1997 with liner notes by Nat Hentoff. The records since have mostly been duos and trios built around a single pianist: Forever with Cesarius Alvim (System Two, Brooklyn, January 29 and 30, 2010), Per Sempre with Teo Ciavarella (Castel Maggiore, Italy, December 2009), Live at Montmartre with Carsten Dahl (November 9, 2011), and Kind of Bill, cut live at the Casinò di Sanremo with Dado Moroni and Joe LaBarbera and released in 2017. In 2009 he and Argentine pianist and arranger Carlos Franzetti won the Latin Grammy for Best Instrumental Album for their duo record Duets (Acqua AQ203). In May 2013 Berklee College of Music awarded him an honorary doctorate of music at its Valencia campus, the first the Spanish campus granted, and he has taught at the Conservatory of Puerto Rico, where he took the post of artistic director. He remains active: Center Stage, a 2022 concert album with Gadd, baritone saxophonist Ronnie Cuber, and the WDR Big Band Köln, and pianist Bob Schlesinger's 2025 debut Falling from Earth, alongside Mike Stern and drummer Billy Drummond, are both recent.

Gómez plays the double bass as a singing instrument, and the conception is traceable to two sources that rarely meet: Frederick Zimmermann's classical pedagogy, which gave him a bow arm and an intonation discipline most jazz bassists of his generation never acquired, and the vocalists he grew up hearing at home. What he does with it is push the bass into the register and the rhythmic freedom of a horn. Where Scott LaFaro had opened the Bill Evans trio to a bass line that answered the piano instead of anchoring it, Gómez extended that opening across eleven years and a much wider range of material, working high on the fingerboard with a bright, cutting amplified tone that he later reconsidered, saying he had come to want the darker microphone sound of Paul Chambers and Ray Brown instead. He names five bassists as the ones who shaped him: Milt Hinton, Chambers, Brown, LaFaro, and Charles Mingus. Evans's own assessment was that "Eddie has the most surprising flexibility," and flexibility is the trait that defined the fifty years after Evans as well, a career that runs from ESP-Disk free jazz at twenty through mainstream piano trios, Japanese fusion dates, Steps Ahead, big band concerts, and pop sessions without settling anywhere. Gómez himself has treated that breadth as a double-edged thing, suggesting that being spread across so many idioms may have cost him a single, unmistakable stylistic signature. What it did not cost him is his standing among bassists: he is one of the small handful of players against whom the modern jazz double bass is measured, and younger bassists on several continents cite him as a model for the acoustic instrument.