Davis was born in Swansea, South-West Wales, on 17 July 1939. His father was a paratrooper during World War II. While his father was away, his uncle Herman was a musical influence on Davis, teaching him how to play the harmonica at age six. While growing up in Swansea, Davis lived through The Blitz: “The bombed city center was my playground. I watched the town being absolutely destroyed.” Davis’ mother continuing to live in the West Cross area of Swansea until her death. He began learning to play harmonica and accordion at the age of six. He attended Dynevor School and became proficient in languages. He moved to London when he was 16 and began working in the civil service as a clerical officer at the Post Office Savings Bank in Hammersmith and then for HM Customs and Excise. However, he went back to his old school to study for A-levels in languages, becoming head boy in 1959. In 1960, he moved to Birmingham, to read German at the University of Birmingham. In music circles, Davis was later known as “Professor”.

In 1963, Davis went to the Golden Eagle in Birmingham to see the Muff Wood Jazz band, a traditional jazz band featuring Muff Winwood and his younger brother, Steve Winwood. Davis persuaded them to join him and drummer Pete York as the Rhythm and Blues Quartet. Davis performed on guitar, vocals and harmonica, Steve Winwood on guitar, organ and vocals, Muff Winwood on bass and Pete York on drums. Reportedly, they adopted the name The Spencer Davis Group because Davis was the only band member who agreed to press interviews, allowing the other band members to sleep longer. The group’s live reputation attracted the attention of Island Records founder Chris Blackwell who signed the group to its first contract and became their manager. The group had No. 1 hits in the UK with consecutive single releases in 1966 (“Keep On Running” and “Somebody Help Me”). Steve Winwood sang lead vocals on all the Spencer Davis Group’s hits up to “I’m a Man” in 1967.

The Spencer Davis Group continued after Winwood left to form Traffic in April 1967. The group recorded two more albums before splitting in 1969. Another version of the group with Davis and York appeared in 1973 and disbanded in late 1974. Various incarnations of the band toured in later years under Davis’ direction.

Davis retained an affinity for Germany, having studied the language and played in clubs in Berlin early in his career. He watched both the wall’s building in the early 60s and almost 30 years later, with his son, the fall of the Berlin Wall in 1989.

In 1993, Davis formed the supergroup the Class Rock All-Stars. He left the group in 1995 to form World Classic Rockers with former Eagles bassist Randy Meisner, singer Bobby Kimball and guitarist Denny Laine.

Davis died from pneumonia in Los Angeles on 19 October 2020 at the age of 81.