He was born in Tripolis in 1880. In 1987 he enrolled in the Athens Law School. In 1904 he became a writer for the Acropolis Newspaper and subsequently the newspaper’s chief editor to 1914 and its director for a brief period beginning in 1920. As a journalist he was director and publisher of the newspapers Nea Hellas (1916), Proodos (1919), of the magazines Odeion (1904), Apollon (1904-1907), Mousiki Epitheorisi [Music Review] (1921-1922), Paraskinia (1938-1939) etc. He wrote books on greek music, among them: The Greek song (1922), History of modern greek music: 1824-1919 (1919) etc. He emerged as a playwright in 1911. He wrote many works that received controversial reviews and were met with reservation by the critics. Forty of those works were turned into commercially successful productions by significant theater companies of his times. The opera The Afternoon of Love [To apogevma tis agapis], by Marios Varvoglis was based on one of his plays. He was one of the founders as well as president of the Electoral Commission and director of the Professional Drama School (1924-1930), member of the Executive Board (1930-1932), of the Artistic Committee (1933) and of the Board of Directors (1943-1946) of the National Theater, professor and director of the Drama School of the National Theater (1930-1946). As a member of the Greek Playwrights’ Society from 1911 and its director from 1932 – 1946, Synadinos played an important role in the founding the Theater Museum. He was one of the main spokesmen for the foundation of the GNO during the interwar period. He was member of the Board of Directors of the National Theater and the National Opera (1943). He was appointed General Director of the GNO twice and under an unfavorable concurrence of events: in 1945-1946 and in 1950-1953. In both cases he fought so that the institution could survive both financially and artistically and did so by putting pressure on the government for the financial support as well as by enriching the repertory. His archive devolved to the E.L.I.A. (The Hellenic Literary and Historical Archive).