In 1941, after Operation Barbarossa began and when he was already a student at Moscow Conservatory, he joined the army as a volunteer, there directing various grass-roots performances, and writing songs and music to dramas.
In 1943–50 (1945–50, according to other sources) he resumed his studies at the Moscow Conservatory under Dmitri Shostakovich and Nikolay Myaskovsky (in composition) and Igor Sposobin (in music theory).
Despite falling seriously ill with schizophrenia in 1951 and in consequence spending a considerable part of his life in hospitals and psychiatric clinics, Galynin remained an active composer.
His work is a bright phenomenon in Soviet classical music though still underestimated, unfortunately, in his homeland and largely overlooked in the West.
"The composer’s bright and original talent was a union of melodic generosity, picturesque harmonies, a sense of modern colouring, and elegance of classical form", the Encyclopedia of Music (Moscow, 1973) wrote of him.