Galdi was born in Naples in 1871. He started as a model and pupil of photographer Wilhelm von Plüschow while he worked in Naples, then he moved to Rome with him, and eventually he ran a studio of his own in Roma between 1900 circa and 1907, taking photos of naked people, especially women. He was probably one of Plüschow's lovers.
After the 1907 scandal and trial that put an end to Plüschow's career, which involved Galdi as well, he abandoned photography. He inaugurated an art gallery in Rome, in Via del Babuino, the "Galleria Galdi", still operating in the 1950s. Rumors about Galdi's death during WW2, circulating in the past, are therefore groundless.