Jackie was born on March 3, 1948 in Brown's Town, in the parish of St. Ann, Jamaica. He was taught piano by his grandmother who was a music teacher, from the age of four and played classical music at an early age. He first performed in public before he was ten, around this time he was playing rags a Jamaican form similar to boogie-woogie and reproducing the American R'n'B he was hearing on the radio. After leaving school Jackie attended Kingston College where he would organize lunchtime jam sessions playing with amongst others Tyrone Downie (later of the Wailers) and Augustus Pablo. He first began playing professionally at the age of thirteen with various bands such as The Rivals and The Sheiks and it was around this time that he started hanging out at Fedral Studios and playing with the cream of Jamaican's musicians who from June, 1964 would become known as the Skatalites.

The Skatalites played a potent mix of jazz arrangements and horn solos over their version of the American R'n'B rhythms so beloved of Jamaica's sound system followers. As the R'n'B style gave way to soul in the USA so the sound system bosses became Jamaica's first record producers, recording one off 'specials' for their exclusive use, to satisfy the demand for R'n'B from their followers. Such was the popularity of these recordings the top 'sounds' began releasing these records to the general public and the Jamaican recording industry was launched into action. The Skatalites recorded for all the top producers of the time Duke Reid's Treasure Isle label, Justin & Philip Yap's Top Deck label as well as Clement 'Coxsone' Dodd's Studio One label.

Dodd's contribution and influence on Jamaican music is immense. After a brief spell working as a cane cutter in the southern states of the USA, Dodd returned in 1954 with the equipment and records to set up his 'Downbeat' sound system which although not the first Jamaican sound was always, along with his great rival Duke Reid's 'Trojan' sound, amongst the greatest. Dodd began recording artists at Fedral Studios in 1959 and it was at a session there, for the singer Delroy Wilson, that Jackie first came to Dodd's attention. The piano player had failed to show and Jackie was asked to stand in, so impressed was Dodd that he asked him to run the sessions at his new studio at 13 Brentford Road in Kingston when it opened in 1963.

Mittoo and Dodd recorded thousands of tunes throughout the Sixties. Singers, vocal groups and dee-jays all backed by a succession of brilliant musicians. When the Skatalites split Dodd formed a new studio band the Soul Brothers under Roland Alphonso's direction, Alphonso was responsible for the horn arrangements whilst Jackie wrote the music. Dodd's basic arrangement with Jackie was to compose five new rhythm a week, Jackie went on to lead the session musicians changing their name to the Soul Vendors and later to Sound Dimension. Jackie wasn't just the leader he was a creator as well, giving the bass player his lines, writing the chords for the guitarist, playing keyboards himself as well as arranging the recordings. The artists recorded during this period included Ken Booth, Bob Andy, Alton Ellis, The Wailers, The Heptones, Marcia Griffiths, John Holt, Slim Smith, Delroy Wilson and many, many others as well as recording superb instrumental music. This body of music is not only the foundation of reggae, constantly being covered and versioned, but an incredible artistic and creative achievement in it's own right.

Jackie left Jamaica for Canada towards the end of the Sixties although he would continue to return regularly and and work with Dodd throughout the Seventies and Eighties. After leaving Studio One Jackie continued to work with many reggae artists and producers most notably Bunny 'Striker' Lee, Sugar Minott's Youth Productions and the Skengdon Recording Company in Miami amongst others.

Jackie Mittoo died of cancer in 1990 leaving behind a legacy of work the importance of which is yet to be fully appreciated.