Bassey was born on 8 January 1937 at 182 Bute Street, Tiger Bay, Cardiff, to a Efik Nigerian sailor father and a mother from Yorkshire, who divorced when she was three. She grew up in the working-class dockside district of Tiger Bay as the youngest of seven children. After leaving Moorland School at the age of fifteen, Bassey first found employment packing at a local factory while singing in local pubs and clubs in the evenings and weekends.

In 1953, she signed up for the revue Memories of Jolson, a musical based on the life of Al Jolson. She next took up a professional engagement in Hot from Harlem, which ran until 1954. By this time Bassey had become disenchanted with show business, and had become pregnant at 16 with her daughter Sharon, so she went back to waitressing in Cardiff.

However, in 1955, a chance recommendation of her to Michael Sullivan, a Streatham-born booking agent, put her firmly on course for her destined career. He saw talent in Bassey, and decided he would make her a star. She toured various theatres until she got an offer of the show that put her firmly on the road to stardom, Al Read's Such Is Life at the Adelphi Theatre in London's West End.

While she starred in this show, Philips A&R and record producer Johnny Franz spotted her on television, was impressed, and offered her a record deal. Bassey recorded her first single, entitled "Burn My Candle", and Philips released it in February 1956, when Bassey was just nineteen.

Owing to the suggestive lyrics, the BBC banned it, but it sold well nonetheless, backed with her powerful rendition of "Stormy Weather". Further singles followed, and in February 1957, Bassey had her first hit with "Banana Boat Song", which reached number eight on the UK Singles Chart. During that year, she also recorded under the direction of U.S. producer Mitch Miller in America for the Columbia label, producing the single "If I Had a Needle and Thread" b/w "Tonight My Heart She Is Crying".

In mid-1958, she recorded two singles that would become classics in the Bassey catalogue: "As I Love You" appeared as a B-side to another ballad, "Hands Across the Sea". It did not sell well at first, but after a chance appearance at the London Palladium things began to pick up. In February 1959, it reached number one and stayed there for four weeks.

Bassey also recorded "Kiss Me, Honey Honey, Kiss Me" at this point, and while "As I Love You" raced up the charts, so too did this record, with both songs being in the top three at the same time. A few months later, Bassey signed to EMI Columbia, and the second phase in her recording career had begun.

Throughout the 1960s, Bassey had numerous hits on the British charts. Her recording of "As Long As He Needs Me" from Lionel Bart's Oliver! reached number two, and had a chart run of 30 weeks. In 1962, Bassey's collaboration with Nelson Riddle and his orchestra produced the album Let's Face the Music (#12) and the single "What Now My Love" (#5).

Other top ten hits of the period included the number-one Double-A side Climb Ev'ry Mountain / Reach for the Stars in 1961, I'll Get By (also 1961) and "I (Who Have Nothing)" in 1963. During this period, John F. Kennedy invited Bassey to sing at his Inauguration Ball. In 1965, Bassey enjoyed her first U.S. top ten chart hit with the title song of the James Bond film, Goldfinger - from the No.1 OST in the US of that year.

Owing to the success of Goldfinger, she appeared frequently on many American television talk shows such as those hosted by Johnny Carson and by Mike Douglas. In the same year, she sang the title track for the spoof James Bond film The Liquidator. In 1968, Bassey performed her song "This Is My Life" at the San Remo Festival in Italy and a version of the song with chorus sung in Italian became a top ten hit on the Italian chart.

Bassey lived as a tax exile for two years in Switzerland from 1968 to 1970, finally returning to the UK in 1970 with a record breaking run of performances at the Talk of the Town nightclub. She signed with the United Artists label in the late sixties and in 1970 released the album Something which showcased a new Bassey style (the single of the same name was more successful in the UK charts than the original Beatles recording).

Something was also a Top 10 US hit on the Adult Contemporary Chart. Other singles of this period included top ten hits "For All We Know" (1971) and "Never Never Never" (1973) - the latter also reaching the Top 10 in the US Adult Contemporary Chart. The success of "Something" (single #4, album #5) spawned a series of successful albums on the UA label, including Something Else (1971), And I Love You So (1972), I, Capricorn (1972) Never, Never, Never (1973), Good, Bad but Beautiful (1975), Life, Love and Feelings (1976), You Take My Heart Away (1977) and Yesterdays (1978).

Two compilations, The Shirley Bassey Singles Album (1975) and 25th Anniversary Album (1978) both made the UK top three. Between 1970 and 1979, Bassey had 18 hit albums in the UK charts. Her 1979 album The Magic Is You featured a portrait by celebrated photograher Francesco Scavullo. In 1973, her sold out concerts at New York's Carnegie Hall were recorded and released as a two LP set Shirley Bassey: Live at Carnegie Hall.

This album and the majority of her recordings from this period have been re-mastered and released on CD by EMI and BGO Records. In 1971, she recorded the title theme for Diamonds Are Forever. The recording featured as part of the main celebration in Sydney, Australia's 2007 New Year's celebration.

In 1976 Bassey starred in the first of her top-rated TV shows for the BBC, followed by a second series in 1979. The final show of the first series was nominated for the prestigious Golden Rose of Montreux in 1977. The series featured guests including Neil Diamond, Michel Legrand, and Dusty Springfield; filmed in various locations throughout the world as well as in the studio. Bassey went on to record her third title theme for the Bond films with Moonraker in 1979.