His father sold artist's materials, while his mother was a dressmaker. Self-taught, he took up the saxophone at 15 to help to alleviate asthma. After minimal coaching he formed the semi-professional New Colorado Band in 1928, and a year later, while working as an office clerk, entered the band in a contest at Chelsea Town Hall, and won. He was spotted by the founding editor of Melody Maker magazine, who was distributing the prizes, and a year later secured his first regular professional position.
In 1933, now married to Kathleen, Gardner was taken under the wing of Ray Noble and recorded with the New Mayfair Orchestra. Gardner was a virtuoso not only on clarinet and alto sax but also on the whole saxophone family. He played in London clubs when working with Sidney Lipton's Orchestra; later with Bert Firman's band, and with Canadian-born Billy Bissett, who spent three years in England from 1936, playing at the Mayfair Hotel, London. Gardner became a prolific record session player, doubling on all the reeds, although his main instrument was alto sax. When Duke Ellington came to London for the first time, Gardner played to Ellington's accompaniment at a club in Wardour Street, to the admiration of the Duke's regular saxophonist, Otto Hardiwcke.
Gardner led small group recordings in 1936/37. Towards the end of 1937, he began to be billed as "Freddy Gardner and his Swing Orchestra", with which he made many recordings. The band included such musicians as George Chisholm and Ted Heath. These were often featured on radio broadcasts, and the band accompanied 'Buck and Bubbles' on their visit to Britain in the late 1930s. Many of the orchestra's arrangements were scored by Gardner himself. He also played with George Scott Wood and his Six Swingers, whose vocalist was Sam Costa, as well as with the Benny Carter Orchestra during Carter's sojourn in Europe.
World War II
During World War II, Gardner joined the Royal Naval Patrol Service (as a diesel engineer) under Eastern Command. An official dance band for the RNPS, called the Blue Mariners, was set up and led by George Crow. Their home was the Sparrow's Nest at Lowestoft, an entertainment centre-cum-theatre appropriated by the Royal Navy. Other musicians in the band were drawn from the orchestras of Henry Hall and Ambrose. Gardner was regularly given special leave to continue his recording and broadcasting. Other recordings at this time were made under the band name 'Freddie Gardner and his Mess Mates'.
After WW II service, he continued with extensive freelance work, including as a soloist with the Peter Yorke Concert Orchestra, which usually comprised between 30 and 40 musicians. This band was formed for the BBC and featured in weekly radio programs such as The Starlight Hour and Sweet Serenade. Gardner's 78rpm recording of "I only have eyes for you" was recorded on 29 April 1948, just two years before his sudden death. Many of his recordings are still available on CD.
Gardner loved golf, all forms of transport and was a keen modeller. He was taken ill while mending one of his sons' bicycles in the garden of his flat near Marble Arch, and though rushed to hospital, he died of a stroke on 26 July 1950 at the age of 39. Many in the profession attended his memorial service and he was buried in Willesden Cemetery.