Martin attended the Guildhall School of Music in the years after World War II, paying his way with a veteran's grant (he had served during the war in the Royal Air Force). Following his graduation, he first worked for the BBC's classical music department, then joined EMI in 1950, as assistant to Oscar Preuss, the head of EMI's Parlophone Records. Taking over Parlophone as Preuss retired, Martin spent his first years with the record label recording classical and Baroque music, original cast recordings of hit plays, and regional music from around the British Isles. He also produced numerous comedy and novelty records, working with offbeat acts such as Peter Sellers, Rolf Harris and Shirley Abicair. Adding rock and roll to Parlophone's repertoire, Martin struggled to find a "fireproof", hitmaking rock artist or group.

He first auditioned the Beatles in 1962, after they had been turned down by Decca Records and most of the major British labels. Although his initial reaction was that "they were pretty awful", Martin signed them to a recording contract. This marked the beginning of a long relationship, in which Martin's musical expertise helped fill the gap between the Beatles's raw talent and the sound they wanted to achieve. Most of the orchestral arrangements and instrumentation (as well as frequent keyboard parts on the early records) on Beatles records were made by Martin, in collaboration with the band. (A good example of this was on "Penny Lane", where Martin worked with McCartney on a piccolo trumpet solo: McCartney hummed the melody, and Martin wrote it down as sheet music.)

Martin's distinctive work on Beatles recordings appears in "Eleanor Rigby", for which he scored and conducted a strings-only accompaniment, "Strawberry Fields Forever", where he turned two very different takes into a single master through careful use of vari-speed and editing, "I Am the Walrus", a quirky and original arrangement (for brass, violins, cellos and choir) effectively complementing the surreal imagery of the song's lyrics, playing a speeded-up Baroque piano solo on "In My Life", and the orchestral 'windup' appearing in "A Day In The Life". He also contributed less praised but integral parts to other songs, including the piano in "Lovely Rita", the circus instrumentation in "Being for the Benefit of Mr. Kite", and the orchestration in "Good Night".

Within the recording industry, Martin is noted for going independent at a time when many producers were still salaried staff A+R men -- which he was until the Beatles' success gave him the leverage to start his own Associated Independent Recording ( and hire out his own services to those artists that requested him.) This arrangement not only demonstrated how important Martin's talents were considered to be by his artists, but also allowed him to take part in the share of record royalties on his hits.

Aside from his work with the Beatles (both group and solo projects), Martin has also produced recordings for many other artists, including the band America and country singer Kenny Rogers. He is also a renowned composer; he scored the Beatles' film Yellow Submarine and the James Bond film Live And Let Die, for which Paul McCartney wrote and sang the title song.

He published a memoir, All You Need is Ears, that both detailed his work with the Beatles and other artists (including Peter Sellers, Sophia Loren, Shirley Bassey, Flanders and Swann, Matt Monro, and Dudley Moore), and gave an informal introduction to the art and science of sound recording.