As a scene-designer, Isaev collaborated with the G. Pitoëff theatre in Paris. In 1937 at the International Exhibition in Paris he designed the pavilion of the Baltic States.

After the World War II, Isaev traveled a lot around France, Switzerland, Italy and Spain. During journeys he created a number of landscapes, frescoes and icons for the Uniate Church in Marseilles and Strasbourg.

Isaev drew illustrations for the magazine C’est Paris. He also illustrated books by Ch. Baudelaire, P. Ronsard, E. Poe and N. V. Gogol.

In 1957 the personal exhibition of the artist was held in New York; in 1949, 1951, 1962, 1964, and 1968 — in Paris. In 1965 Isaev exposed his works at group exhibition of European art in New York. He also exposed his works at the Russian thematic exhibitions Russian artists of Paris School (1961) and Russian View (1974).

In 1976 the posthumous personal exhibition of Isaev’s works was held in Paris.

In his landscapes Isaev tried to combine realism and cubism. His paintings were figurative, decorative and were saturated of color.

Works by Nikolay Isaev are in the Museum of Modern Art in Paris, museums of Zurich, Chicago and in private collections.