Giacomelli was a self-taught photographer. At 13, he left high school, began working as a typesetter and spent his weekends painting. After the horrors of World War II, he turned to the more immediate medium of photography. He wandered the streets and fields of post-war Italy, inspired by the gritty Neo-Realist films of Vittorio De Sica and Roberto Rossellini, and influenced by the renewed Italian photographer Giuseppe Cavalli, and developed a style characterized by bold, stylized compositions and stark contrasts.
Giacomelli’s most successful series, I Pretini (Little Priests) (1957), a poetic transcription of the everyday life of a group of young priests, resulted from documenting Post-War Italian seminaries.