In his first band, rock'n'roll combo El Riot and the Rebels, Pinder played support to the Beatles in 1963 in a show at Tenbury.

[5] In May 1964 he left Streetly Electronics to co-found The Moody Blues with Ray Thomas, Denny Laine, Clint Warwick and Graeme Edge.

Pinder and Laine began a songwriting partnership, providing most of the band's B-sides from 1964–66, including "You Don't (All The Time)", "And My Baby's Gone", "This Is My House (But Nobody Calls)" and "He Can Win".

Pinder was partly responsible for the choice of young Swindon guitarist, vocalist and songwriter Justin Hayward to replace Laine.

[1] Hayward's "Fly Me High" was the first single from the revised line-up, released on Decca in early 1967, with Pinder's old-style rocker "Really Haven't Got the Time" as the B-side.

Pinder acquired a second-hand Mellotron from Streetly Electronics, and after removing all the special effects tapes (train whistles, cock crowing, etc.)

and doubling the string section tapes, used it on numerous Moody Blues recordings, beginning with their single "Love and Beauty", a flower power song written and sung by Pinder, which was his only A-side after 1966.

[5] His "Dawn (Is A Feeling)", with lead vocals by Hayward and Pinder singing the bridge section, opened the Days of Future Passed album.

Pinder also contributed "The Sunset" and narrated drummer Edge's opening and closing poems, "Morning Glory" and "Late Lament".

Days of Future Passed had been planned as a stereo demonstration album for the Decca Deram label, combining rock and orchestral music.

[1] Pinder, Moody Blues recording engineer Derek Varnals and long-time producer Tony Clarke (a Decca staff producer assigned to them from "Fly Me High" onwards), devised an innovative way of playing and recording the unwieldy Mellotron to make its sound flow in symphonic waves, rather than with the instrument's usual sharp cutoff.

Pinder was one of the first musicians to use the Mellotron in live performance, and he had to rely on the mechanical skills he had gained from his time as an engineer with Streetly Electronics to keep the instrument functioning.

Pinder got the instrument back into working order in 20 minutes while the lighting crew entertained the audience by projecting cartoons.

On Moody Blues recordings from 1967 onwards, in addition to the mellotron, organ and piano, Pinder also played harpsichord, Moog synthesizer, tablas, various forms of keyboards and percussion, autoharp, tanpura (tambura), cello, bass and acoustic and electric guitars.

Pinder's earlier non-album song "A Simple Game" (1968), for which he won an Ivor Novello Award, was used as the B-side of the group's UK hit single "Ride My See-Saw" from In Search of the Lost Chord.

His composition and lead vocal, "My Song", a deep, reflective, and atmospheric piece, concluded the Moody Blues' 1971 album Every Good Boy Deserves Favour.

This, along with an impending divorce, prompted him to re-locate to Malibu, California, where he recorded a solo album The Promise in 1976, released through the Moody Blues' Threshold label.

Pinder took employment as a consultant to the Atari computer corporation (primarily working on music synthesis), remarried, and started a family in Grass Valley, California.

As his first spoken word album, it was well received among its contemporaries in the genre – it was a finalist for the Benjamin Franklin Award for Excellence in Audio as an outstanding children's recording.

Some fans and critics took his decision to be a silent protest against the Rock and Roll Hall of Fame for its perceived snub of the group in previous years.

All three of his sons became musicians: his eldest, Daniel, is a film music editor and consultant with many credits, including Pirates of the Caribbean: The Curse of the Black Pearl and The Da Vinci Code.

Matt and Michael Lee perform as The Pinder Brothers and have issued a number of CDs, including Jupiter Falls and Ordinary Man; in 2015 they released Melancholy Sea.