Józef Gardecki was born in Warsaw's Wola district as the son of Józef, a cab driver, and housewife Waleria née Korytkowska. He grew up in a modest home, and at the age of 12 began his artistic education at the Warsaw Drawing School on Teatralny Square, where he formed a long-term friendship with the artist Jan Rembowski. After graduating from the school, he began to learn the trade of a pewterer at the Norblin silver and platinum factory, from which he graduated as a journeyman in the bronze and goldsmith's craft. In the meantime, he ran an amateur employee theatre.

In 1901, he began his studies at Kraków's Academy of Fine Arts and in 1905 married Jadwiga Rudnicka. After the wedding ceremony, the couple visited Rudnicka's brother, imprisoned in the Pawiak prison for revolutionary activity. Gardecki helped the workers' movement under the partitions by smuggling illegal publications of the Polish Socialist Party, which he distributed to workers and peasants. In the following years he went to Paris, where he was given sculpture lessons by Auguste Rodin between 1907 and 1909. From 1910 he ran a sculpture and art studio in Warsaw, active until 1926, although he left for Sweden for the duration of the First World War. Both before and after the war he was involved in architectural work, working on the European Hotel and the Old Theatre in Krakow, among others. From 1926 he devoted himself mainly to sculpture and writing. He was friends with, among others, Stefania Sempołowska and Władysław Tatarkiewicz.

He lost all his artistic output during the Warsaw Uprising, when his flat and studio were burnt down in a fire. He died in 1952 and was buried in the Powązki Cemetery.