The group exhibited in Sweden and internationally over 1949–51, supported by the newspaper Svenska Dagbladet's cultural critic Ull Hård al Segerstad and Aftonbladet's Kurt Bergengren.

Malmberg subsequently went freelance in 1949, and his work appeared in Carl Adam Nycop's Se magazine 1949–1958 including reportage on the Korean War in 1950 totalling about fifty pages over eight issues; in Vi from 1958 and through the 1960s; and in Stockholms-Tidningen.

He also covered the USA, Korea, Suez, Egypt, Iran, Cuba and various countries in Europe, later also from Africa and Southeast Asia, developing a subjective language with a human warmth and solidarity.

With Sten Didrik Bellander (1921–2001), Harry Dittmar, Sven Gillsäter (1921–2001), Rune Hassner(1928–2003), Georg Oddner(1923–2007), Lennart Olson (1925–2010), Hans Hammarskiöld (1925–2012), Tore Johnson, and Pål Nils Nilsson, he was a member of the professional collective Tio Fotografer ('Ten photographers') formed in 1958 and their subsequent photo agency Tiofoto.

[5] Malmberg was twenty-seven when curator Edward Steichen selected his photograph of a Swedish bride, backlit by low sunlight and being greeted by her groom at the door of the chapel, for the Museum of Modern Art's 1955 world-touring exhibition The Family of Man seen by 10 million visitors, and in its catalogue.