In 1948, together with Lee Hays and other veterans of the Almanacs, Seeger formed the Weavers. It was never as successful, but it kept the radical flame alive through the 1950s McCarthy witchhunts. The successor to People's Songs was Sing Out!, a mini-movement and magazine of topical songs. It was left badly exposed politically by its participants' intense involvement in the radical 1948 Progressive party presidential campaign of Franklin D Roosevelt's former vice‑president Henry Wallace. At first welcomed by the press and labour organisations, People's Songs fell victim to the cold‑war atmosphere. A quasi-political movement with far-flung chapters and a booking agency, People's Songs furiously promoted the 'hootenanny' – informal sessions where musicians and fans traded songs and shared leftwing political enthusiasms. In December 1945, a group of musicians, choral directors and union educators met at Seeger's New York apartment to form People's Songs. The following year he married Toshi Ohta. Seeger was drafted into the army and went to the Pacific in 1942. The group dissolved as various members were called to second world war duty.

The Sinking of the Reuben James, written by Guthrie, became an anthem of battle courage, the Office of War Information hired them to sing for overseas broadcasts to US troops – and the FBI watched them closely. However, the Almanacs regained some respectability with their musical tributes to the war effort. The album Talking Union (1941-42) was adopted by American labour activists for generations, and the group, which was soon joined by the folk singer Woody Guthrie, also recorded anti-war ballads, which proved embarrassing when Nazi Germany invaded the Soviet Union, the Japanese bombed Pearl Harbor, and the American left became ferociously patriotic. Seeger made his first recordings in New York in 1940 with the Almanac Singers musical collective. But above all, Seeger, blacklisted in the mid-1950s at the height of McCarthyism, was a deeply radical American.

A multitude of artists recorded his work across six decades, including Odetta, Bruce Springsteen and Peter, Paul and Mary, and he recorded more than 100 albums himself. He wrote Where Have All the Flowers Gone? and helped make famous We Shall Overcome. The singer, banjo player and songwriter Pete Seeger, who has died aged 94, popularised folksong performance during the 1940s and 50s and was a key figure in the folk revival from the 60s onwards.

Arlo guthrie pete seeger