She never stopped recording - over 50 years and over a 1,000 songs and still counting! In 1949, Clark branched into recording with her first release, "Put Your Shoes On, Lucy," for EMI. 

But,  because neither EMI nor Decca, for whom she also had recorded, were keen to sign her to a long-term contract, her father, whose own theatrical ambitions had been thwarted by his parents, teamed with Alan A. Freeman to form Polygon Records in order to better control her singing career.

She scored a number of major hits in the U.K. during the 1950s, including "The Little Shoemaker" (1954), "Majorca" (1955), "Suddenly There's a Valley" (1955) "With All My Heart" (1956) and "Alone"(1957) .

Near the end of 1955, Polygon Records was sold to Nixa Records, then part of Pye Records, which lead to the establishment of Pye Nixa Records (subsequently simply Pye). This turn of events effectively signed Clark to the Pye label in the U.K., for whom she would record for the remainder of the 1950s, throughout the 1960s, and early into the 1970s.

In answer to the rock-and-roll craze of the late fifties, Pet recorded Baby Lover, Sailor, Romeo and My Friend The Sea and was back on the charts again.

In 1961, Pet went to France to sing one song at a concert and they went completely bonkers over her.

Asked to record in French, Pet declined at first, but was later persuaded to do so by Frenchman Claude Wolff with whom she fell madly in love - they were married in June 1961. (They had three children, Barra, Katy, and Patrick). Petula really matured as a singer on the Continent with smash hit after smash hit in French, German, and Italian. Urged by her friends in Britain to record something in English, Pet allowed Tony Hatch to visit her in Paris where he presented his new song, "Downtown". Pet recorded it and it skyrocketed to number 1 in the USA. She quickly followed with "I Know A Place" that went to number 3. Petula received a Grammy for "Downtown" in 1964 and another for "I Know A Place" in 1965. All told, Pet has 15 top 40 hits in the USA (two #1 hits). Internationally, Petula Clark has charted in the top 40 somewhere, sometime, with 159 recordings. Her career caught up in a whirlwind, she has ridden it like the pro that she is. Numerous TV appearances both on her own specials as well as on the American TV shows, Ed Sullivan, Dean Martin, Tom Jones, Here's Lucy, the Muppets, Shindig, Hullabaloo.

1966 brought "I Couldn't Live Without Your Love" and the number one smash "My Love." At the same time, she remained a huge star throughout Europe, topping the British charts in 1967 with "This Is My Song," taken from the film A Countess From Hong Kong. In addition to hosting her own BBC series, she also starred in the 1968 NBC television special Petula, which triggered controversy when sponsors requested that a segment with guest Harry Belafonte be cut in deference to Southern affiliates; ultimately, the show aired in its intended form. As the 1960s drew to a close, Clark's commercial stature slipped, although singles like "Don't Sleep on the Subway," "The Other Man's Grass Is Always Greener" and "Kiss Me Goodbye" still charted on both sides of the Atlantic. In 1968 she revived her film career by starring in Finian's Rainbow , followed a year later by Goodbye, Mr. Chips .

In later years Clark focused primarily on international touring, headlining the 1981 London revival of Rodgers and Hammerstein's The Sound of Music. After starring in the 1990 musical Someone Like You , which she also co-wrote, she made her Broadway debut in Blood Brothers in 1993. Additionally, in 1988, an acid-house remix of "Downtown" reached the U.K. Top Ten, another honour for the female singer awarded the most gold records in British pop history.

In 1997, Queen Elizabeth made Clark a Commander of the Order of the British Empire.