He was the engineer on all of the EMI studio recordings by the Beatles until 1965, when EMI promoted him from engineer to producer. The last Beatles album he recorded was Rubber Soul, and Smith engineered the sound for almost 100 Beatles songs in total.
John Lennon first bestowed upon Smith the nickname of "Normal", and it was quickly picked up by the other Beatles. Lennon did so as a humorous reference to Smith's very unhurried and unflappable nature.
While working with The Beatles on 17 June 1965, he was offered £15,000 by the band's music publishing company, Dick James Music, to buy outright a song he had written.
In early 1967, he began working with a new group, Pink Floyd, producing their first, second, and fourth studio albums The Piper at the Gates of Dawn, A Saucerful of Secrets, and Ummagumma. During the sessions for the song "Remember a Day", drummer Nick Mason became agitated that he could not come up with the right drum part for the song. Smith, however, knew what he wanted with the drums, so he played the part himself....
...In 1971, Smith, using a recording artist pseudonym of Hurricane Smith, had a UK No. 2 hit with "Don't Let It Die". This recording was a demo of a song that he had written with the hope that John Lennon would record it. When he played it for fellow record producer Mickie Most, Most was impressed enough to tell him to release it as it was. In 1972, he enjoyed a transatlantic hit with "Oh, Babe, What Would You Say?", which became a US No. 1 Cash Box and a Billboard Pop No. 3 hit. It reached No. 4 in the UK Singles Chart