Bangs was born in Escondido, California. He was the son of Norma Belle (née Clifton) and Conway Leslie Bangs, a truck driver. Both of his parents were from Texas: his father from Enloe and his mother from Pecos County. Norma Belle was a devout Jehovah's Witness. Conway died in a fire when his son was young. When Bangs was 11, he moved with his mother to El Cajon, also in San Diego County. His interests and influences growing up were as wide-ranging as the Beats (particularly william S. Burroughs), jazz Musicians like John Coltrane and Miles Davis, comic books, and science fiction. He had a connection with the San Diego Door, an underground newspaper of the late 1960s.

In 1969 Bangs became a freelance Writer after reading an ad in Rolling Stone soliciting readers' reviews. His first piece was a negative review of the MC5 album Kick Out the Jams, which he sent to Rolling Stone with a note requesting that if the magazine were to decline to publish the review, he would be given a reason for the decision; no reply was forthcoming, as the magazine did indeed publish the review.

During the early 1970s, Bangs and some other Writers at Creem began using the term punk rock to designate the genre of 60s garage bands and more contemporary acts, such as MC5 and Iggy and the Stooges. Their writings would provide some of the conceptual framework for the later punk and new wave movements that emerged in New York, London, and elsewhere later in the decade. They would be quick to pick up on these new movements at their inception and provide extensive coverage of the phenomenon. Bangs was enamored of the noise music of Lou Reed, and Creem gave significant exposure to artists such as Reed, David Bowie, Roxy Music, Captain Beefheart, Blondie, Brian Eno, and the New York Dolls years before the mainstream press. Bangs wrote the essay/interview "Let Us Now Praise Famous Death Dwarves" about Reed in 1975. Creem was also among the earliest publications to give sizable coverage to hard rock and metal artists, such as Motörhead, Kiss, Judas Priest, and Van Halen.

In 1973, Jann Wenner fired Bangs from Rolling Stone for "disrespecting musicians" after a particularly harsh review of the group Canned Heat.

Bangs was also a musician in his own right. In 1976, he and Peter Laughner recorded an acoustic improvisation in the Creem office. The recording included covers/parodies of songs like "Sister Ray" and "Pale Blue Eyes", both by the Velvet Underground.

In 1977, at the famous New York City nightclub, CBGB's, while Lester was talking to Guitarist Mickey Leigh, Joey Ramone's brother, the idea for a band named "Birdland" came to fruition. Although they both had their roots in jazz, the two wanted to create an old school rock & roll group. Leigh brought in his post-punk band, The Rattlers (David Merrill on bass; Matty Quick on drums), and cut "Birdland with Lester Bangs". The recording took place at the under renovation Electric Lady Studios. Bassist David Merrill, who was working on the construction of the studio, had the keys to the building and they snuck the band in on April Fool’s Day, 1979 for an impromptu and somewhat illegal late night recording session. The end result was a completely uncut and un-dubbed recording that displayed completely raw music. Birdland broke up within two months of this rare recording (in which the cassette tape from the session became the master, mixed by Ed Stasium and released by Leigh only in 1986).

In 1980 Lester Bangs traveled to Austin, Texas, and met a surf/punk rock group "The Delinquents". In early December of the same year, they recorded an album as "Lester Bangs and the Delinquents", entitled Jook Savages on the Brazos, released the following year.

Bangs died in New York City on April 30, 1982, at the age of 33, of an accidental overdose of dextropropoxyphene (cough medicine), diazepam (Valium), and NyQuil.

In 1990 the Mekons released the EP F.U.N. 90 with Bangs' declamation in the song "One Horse Town".