Hiram Law Bullock was born on September 11, 1955, in Osaka, Japan, to African American parents serving in the U.S. military, and was brought back to Baltimore, Maryland, at the age of two. He studied piano at the Peabody Conservatory and gave his first public performance at six, learned saxophone at around eleven, played bass guitar in junior-high rock bands, and switched to electric guitar at sixteen. He attended the McDonogh School in Reisterstown, Maryland, and then the University of Miami's music school, where he met the guitarists Pat Metheny and Steve Morse and the bassists Jaco Pastorius and Will Lee, and where a steady nightclub job with the singer Phyllis Hyman eventually pointed him toward New York.

In New York in the mid-1970s he worked with the Brecker Brothers and with David Sanborn, and there he met the producer Phil Ramone, who put him on a long run of pop sessions. Discogs credits him with electric guitar on Billy Joel's The Stranger (1977), guitar on the Brecker Brothers' Don't Stop the Music (1977), the track "My Rival" on Steely Dan's Gaucho (1980), "That's Why God Made the Movies" on Paul Simon's One-Trick Pony (1980), electric guitar and a vocal on Bob James's H (1980), and "Little Wing" on Sting's ...Nothing Like the Sun (1987). He also recorded three albums with the 24th Street Band, released in Japan in 1979, 1980 and 1981, the last of them Bokutachi.

His own recording career began in 1982 with First Class Vagabond, a Japanese release on Trio that he produced, with Will Lee on bass, Steve Jordan and Charley Drayton on drums, Paul Shaffer and Clifford Carter on keyboards, and Sanborn on saxophone. The same year he became an original member of Shaffer's World's Most Dangerous Band, the house band on NBC's Late Night with David Letterman, where his barefoot stage presence made him a recognizable figure for about two years. He also played in the house band on Saturday Night Live and later served as musical director of Sanborn's Night Music television series. In 1983 he joined Gil Evans's Monday Night Orchestra at the New York club Sweet Basil, and Discogs lists his guitar on four of the orchestra's live albums issued between 1985 and 1988. In 1983 he also produced and played second guitar on Mike Stern's debut Neesh, and in 1984 he played on Carla Bley's Heavy Heart.

Atlantic released his first American leader albums, From All Sides (1986), Give It What U Got (1987) and Way Kool (1992), all produced by Bullock. From All Sides has Lee on bass, Drayton on drums, Kenny Kirkland and Carter on keyboards, and guest solos by Sanborn and Michael Brecker; Give It What U Got adds Randy Brecker, Michael Brecker and Lew Soloff and has Al Jarreau singing lead on one track. In 1989 the Japanese label DIW issued PDB, a live recording made at Jonathan Swift's in Boston on February 1, 1986, as a trio with Jaco Pastorius and the drummer Kenwood Dennard. His 1990s and 2000s albums spread across styles: World of Collision (Big World Music, 1994) is a rock-leaning set produced with Lee and Drayton; Carrasco (Fantasy, recorded April 3 to 5, 1997) uses candombe drummers and Latin percussion; Late Night Talk (Venus, recorded December 1996 at RPM Studio in New York) is an organ-based date with Dr. Lonnie Smith on B-3, Idris Muhammad on drums, bassist Ed Howard and vibraphonist Joe Locke; and 55 Bar Sessions (1998) was taped live at the New York club of that name with Haru Takauchi, Leni Stern and Mike Stern sharing the guitar duties. Color Me (1999) and Guitar Man (2000) came out on JVC, Try Livin' It on ESC in 2003, and Too Funky 2 Ignore on BHM in 2005, with the singer Claudia Acuña on one track.

In 2004 he toured Europe with the Soul Bop Band, a quintet co-led by the saxophonist Bill Evans and Randy Brecker with bassist Victor Bailey, drummer Steve Smith and keyboardist David Kikoski, documented on a live CD in 2005. On May 27, 2004, he played a program of Jimi Hendrix music at the University of Cologne with drummer Billy Cobham and the WDR Big Band, released as Plays the Music of Jimi Hendrix in 2008, and in December 2007 he recorded a Christmas program with the same band at the Stadtgarten in Cologne, issued in 2013 as Christmas Revisited. His longtime partner, Jennifer Armstrong, told the New York Times that he was diagnosed with cancer of the tongue in the fall of 2007. He passed away in New York City on July 25, 2008, at 52. Shaffer said afterward that he considered Bullock the greatest guitarist ever, with Hendrix perhaps the only exception.

Bullock is best described as a jazz-funk and fusion guitarist who spent most of his working life in rooms where jazz was only one of the languages. English Wikipedia files him under jazz-funk and jazz fusion guitarists, and the New York Times called him a soulful and adaptable jazz and rock guitarist. His own description of his music, repeated on his All About Jazz profile, was a blend of rock, funk, blues and jazz, and his albums moved between the contemporary jazz of From All Sides, the rock of World of Collision, the Latin colors of Carrasco and the organ-based jazz of Late Night Talk. His playing was built on bluesy string bending, a big electric tone and a showman's presence (he played barefoot, and Cort built signature HBS and HBS-II models for him). He studied with Pat Metheny and Jaco Pastorius in Miami, was mentored by Phil Ramone in New York, and carried a rhythm guitarist's sense of pocket into everything from David Sanborn's bands to Gil Evans's orchestra. A large share of his recorded legacy is pop and rhythm-and-blues session work and television band playing, and that is part of why he is better known to a general audience than to jazz listeners; the jazz thread runs through his Sanborn, Evans, Stern and Pastorius associations, his own fusion and organ-based albums, and his late work with the WDR Big Band.