Kalatzis was born in Thessaloniki on April 29, 1943. He started singing in the early 1960s as a member of the "Trio Moreno". Later, he moved to Athens, where he shot to popularity in 1968, with such songs as "Delfini, delfinaki", "To palio roloi", "Ta chrysa kleidia". In 1969, he followed up with "O epipolaios".
Kalatzis continued being popular in the early 1970s with such hits as "Gorgona", "O Stamoulis o lochias", "Jamaica", "Paramythaki mou" and his mega-hit "Kyra-Giorgaina". "Xenaki" and "Koutalianos" followed later, the latter song being a satyrical tribute to legendary strongman Panagis Koutalianos.
Kalatzis gave up active singing in the 1980s as his popularity declined but, in 1985, he took part in a big concert dedicated to the memory of composer Manos Loizos that took place in Athens Olympic Stadium.
The songs of Kalatzis are still popular in Greece and have been performed by other singers as well. He has released a couple of 'best of' albums.