At 15, he went on to study with the gifted Jungarian classical pianists, Paul de Marky. During these early years, Peterson won the Ken Soble amateur radio show, began his own studio program, "Fifteen Minutes Piano Rambling," on CKAC in Montreal, and after several appearances on local radio as a guest artist, was featured nationally on the CBC's "Light Up and Listen" and "The Happy Gang." Soon thereafter, Peterson became a member of the Johnny Holmes Orchestra, and in 1947 he formed his first Canadian trio with Austin "Ozzie" Roberts on bass and Clarence Jones on drums, or, briefly Ben Johnson on guitar. He was signed up by RCA Victor Records and made various tours across Canada.

In 1949, Oscar Peterson accepted an invitation from US impresario Norman Granz to be a surprise guest on "Granz's Jazz at the Philharmonic" at Carnegie Hall. Under the guidance of Granz, who was to be his manager for over 30 years, Peterson formed a trio in the USA in 1951 that included Ray Brown on bass and commenced recording for Granz under his Verve label. He then pursued his career internationally, touring the United States, Europe, Africa, South America, the Far East, and the Soviet Union. He has played at many Canadian and European jazz festivals such as the Festival international de jazz de Montreal and the Montreux Festival in Switzerland. Since 1958, he has made his home in Toronto.

Peterson is equally accomplished as a composer, and one of his earliest works is the Canadiana Suite (1963), which earned him international acclaim. His other works include African Suite, Hallelujah Time, Blues for Big Scotia, Blues for Smedley, The Smudge, Bossa Beguine and Hymn to Freedom. His Hymn to Freedom became one of the crusade hymns of the Civil Rights Movement in the Board (NFB), the BBC and for other film and television projects. His composition of the sound track for Norman McLaren's NFB film Begone Dull Care (1949) was well received all over the world, and he won a Canadian Film Award in 1978 for his score for the movie thriller The Silent Partner. Other film scores include Big North and Fields of Endless Day.

Oscar Peterson has starred in and hosted several television programs and specials. He was host of CTV's "Oscar Peterson Presents" and the BBC TV's "Piano Party" in the mid-1970s, and in 1980 he appeared on the CBC series "Oscar Peterson and Friends". Since then, he has appeared on various programs on French and English television. He will be celebrated at the Gala Screening of In The Key Of Oscar, a film documenting his struggles and triumphs, on 15 October at Roy Thomson Hall in Toronto.

Peterson has won many awards throughout his career. In 1950, he was voted best jazz pianist for the year by the readers of Down Beat, an award he would receive for 12 years. He was named Officer of the Order Of Canada in 1972 (promoted to Companion in 1984), received the Queen's Medal in 1977, became a member of the Juno Awards Hall of Fame in 1978, and in 1989 was made an Officer of Arts and Letters, France. He has received seven Grammies and 11 Grammy nominations and won a Juno in 1987. In 1991, he was the recipient of the Toronto Arts Awards for lifetime achievement. He holds 10 honorary doctorates from American and Canadian universities, and in 1991, he became Chancellor of York University in Toronto.