It was thanks to the folk singer Judy Collins that David Clayton-Thomas, who has died aged 84, joined Blood, Sweat & Tears and helped to drive the band to the forefront of the exploding late 1960s rock scene. Clayton-Thomas, a singer and songwriter, had been performing in Toronto with his own groups, the Shays and the Bossmen, and had scored a hit with the latter band on the Canadian chart in 1966 with his anti-Vietnam war song Brain Washed.

Collins was a friend of the drummer Bobby Colomby, one of the founders of Blood, Sweat & Tears, and knew they had just lost their vocalist and keyboard player, Al Kooper. When she heard Clayton-Thomas sing at a gig in New York, she suggested him as a replacement, an inspired notion that helped to power Blood, Sweat & Tears into the big time.

The band’s debut album, Child Is Father to the Man, had cracked the US Top 50, but it was the follow-up, Blood, Sweat & Tears (released in December 1968), with Clayton-Thomas now on board, that blasted them into the rock’n’roll stratosphere.

The mixture of his gritty and soulful tenor voice with the band’s punchy four-piece horn section and imaginative arrangements, as well as Clayton-Thomas’s burly physical presence, created a formidable musical brew, mixing jazz, blues, soul and balladry. The album not only topped the US chart but generated three hit singles, which each reached No 2 in the US, You’ve Made Me So Very Happy, And When I Die and Spinning Wheel, the last of these a Clayton-Thomas composition. The album would win the Grammy for album of the year, and was voted into the Grammy Hall of Fame in 2002.

The band were one of the headlining acts at the 1969 Woodstock festival, and topped the US album charts again with Blood, Sweat & Tears 3 (1970), which also gave them a Top 20 hit single with Hi-De-Ho and a Top 30 showing with Lucretia Mac Evil.

But they ran into controversy when they became the first American band to tour behind the iron curtain, visiting Yugoslavia, Romania and Poland under the auspices of the US State Department that year. Clayton-Thomas commented to Rolling Stone magazine: “We went over there with the idea of just how much so-called communist fascism is American propaganda, and I found that the propaganda is pretty damn close to the truth. It’s scary.”

The band’s seeming collusion with the reviled Richard Nixon administration went down badly with parts of their audience, but it was not until the release of the 2023 documentary film What the Hell Happened to Blood, Sweat & Tears? that the full story was revealed. Clayton-Thomas had a criminal record from his youth in Canada, and faced being deported from the US for overstaying his visa. He and the band were told that if they agreed to undertake the tour, he would be granted permanent US residency.

Their fourth album B, S & T; 4 (1971)reached only 10 on the album chart and spawned a minor hit single with Go Down Gamblin’ (a Clayton-Thomas composition). After its release he quit the band to pursue a solo career. Arguments over business issues and a surfeit of drugs and alcohol had tested inter-band relationships to their limits.

Clayton-Thomas released three solo albums in 1972-73 before rejoining the group in 1974. He released a further 14 solo albums between 1977 and 2019, though none of them made an impact on the charts. Similarly, while Blood, Sweat & Tears released new studio albums regularly up to Nuclear Blues (1980), only one, New City (1975), reached the US Top 50.

David was born in the UK, in Kingston upon Thames, Surrey, during the second world war. He was the son of Fred Thomsett, a Canadian soldier, and Freda (nee Smith), a music student whom Fred met when she came to play the piano for soldiers at a London hospital.

After the war the family relocated to the Toronto suburb of Willowdale, but by the age of 14 David had left home and was living rough, due to maltreatment by his alcoholic father. He was arrested several times for vagrancy and theft, and it was during a period of incarceration that he began teaching himself the guitar on an instrument left behind by a former inmate.

He began performing at clubs in the Yonge Street district of Toronto, initially under the name Sonny Thomas, earning recognition for his raw and muscular blues singing. He sometimes performed with the Hawks, who would become Bob Dylan’s backing group and renamed themselves the Band. Adopting the name Clayton-Thomas marked a move to get away from his troubled youth.

The first band he formed was an R&B outfit, the Shays – originally David Clayton-Thomas and the Fabulous Shays (who were the opening act for the Rolling Stones at Maple Leaf Gardens in Toronto in 1965) – before he teamed up with the jazz pianist Tony Collacott in the Bossmen. He followed this by forming the David Clayton-Thomas Combine, before accepting an invitation from the bluesman John Lee Hooker to travel to New York and perform in the Greenwich Village clubs. It was there that he met Collins and made the Blood, Sweat & Tears connection.

In 2010, Clayton-Thomas published his autobiography, Blood, Sweat and Tears. He was a regular campaigner for Peacebuilders Canada, a non-profit organisation seeking changes in justice and education to “keep young people out of the criminal justice system”.

Four marriages ended in divorce. He is survived by two daughters, Ashleigh and Christine.

• David Clayton-Thomas (David Henry Thomsett), singer and songwriter, born 13 September 1941; died 24 June 2026