Constantine Kyriazopoulos was educated in his birthplace of Adrianopole, Greece, before attending the School of Medicine in Athens. He qualified as a Doctor of Medicine in 1891, and subsequently studied Pathology and Obstetrics in Paris for two years. Kyriazopoulos worked in Bulgaria as a travelling government doctor before coming to Melbourne in 1902. He was one of the first qualified Greek doctors in Australia, although his medical qualifications were not initially recognised. By 1909 he had established himself both in the Australian Greek community and in Melbourne's medical circles. From 1926 he was known in medical circles by the name Krizos.
His only surviving work is O Adiakritos Mousaphires (The Inconsiderate Guest), a one-act comedy published in Athens in 1923. This social comedy of manners combines drama and poetry, and Kyriazopoulos said he had borrowed the idea for the play from the diary of the Athenian satirist Constantine Skokos. The play was first produced in Melbourne in 1917 in aid of Greek children orphaned by World War I.
From 1913, Kyriazopoulos wrote prolifically in Greek-language Australian newspapers, often under the pseudonym Ktilos. His essays discussed a range of historical, social and medical subjects, and he also wrote articles about the Greeks for the Australian public. He was a leading figure in Greek community affairs in Melbourne and a member of many public associations. When he died in 1939, long obituaries were published in Phos, 23 August 1931, p. 1; and in Panellinios Kyrykas, 7 September 1939, p. 7.