During his youth, Henri Krasucki involved himself in cooperative movements, before entering the Renault factory where he began activism as a trade-unionist.

Under the Vichy regime, he took part to the FTP-MOI Communist resistance movement composed of immigrants under the pseudonym Mésange (Bluetit).

Tortured in the Fresnes prison, where he was detained for six months, Henri Krasucki didn't break under interrogation and kept silent.

In 1956, he entered the central committee of the PCF, and then in 1961, the confederal bureau of the CGT, before becoming the director of the union's mouthpiece, La Vie ouvrière.

Until the beginning of the 1980s, Krasucki defended some of the most rigid orientations of the PCF, leading him to somehow oppose himself to Georges Séguy, who was attempting, since 1978, to preserve the CGT from the consequences of the rupture of the Left-wings' Union, which had taken place in October 1977.

Although the beginning of his leadership of the CGT witnessed a radicalization of the union, he undertook a progressive evolution towards more "negotiation" with the government at the end of his mandate and took his distances with the PCF.

[citation needed] He is portrayed by actor Adrien Jolivet in the 2009 French film The Army of Crime directed by Robert Guédiguian.