In 1949, he directed the short documentary O Desterrado, a film about the life and craft of the Portuguese sculptor Soares dos Reis.
Being constantly attacked by the regime, Guimarães opted to direct more commercial movies about sport events, since 1956.
In his attempt to return to fiction, (A Costureirinha da Sé – 1958) Manuel had to accept product placement in the film.
António da Cunha Telles, who meanwhile began to produce the first films of the Portuguese Cinema Novo (New Cinema), became interested in him and accepted to do an executive production and co-production of two of his next films: O Crime da Aldeia Velha (1964), an adaptation of a Bernardo Santareno play and O trigo e o Joio (1965) based in the book with the same name, by Fernando Namora, who wrote the script as well.
Ill, Manuel Guimarães couldn't end his last film, Cântico Final, adapted from the novel with the same name wrote by Virgílio Ferreira.