Kondratov studied from 1910 to
1915 at the Moscow Stroganov Institute and from 1919 to 1923 at the
Moscow Vkutemas. In 1926 he joined the group OST. He lived and worked in
Moscow and participated to the ornamentation of its squares and streets
during the big Soviet festivals. In the 1920s and 1930s he worked as a
scenographer for the children's theatres in Leningrad and Moscow. In the
first half of the 1930s he worked as an illustrator of children's books
for the State Publishing House and Molodaia Gvardiia.