Constantin Isachie Popescu was a Romanian painter whose career combined rigorous academic training with a lifelong commitment to plein-air painting. Born in Pașcani, he initially pursued studies in commerce and law, but his artistic vocation prevailed when he enrolled at the School of Fine Arts in Bucharest under the guidance of G. D. Mirea. In 1919, he travelled to Italy to study at the Royal Academy of Fine Arts in Florence with Guido Colucci, graduating with the highest distinction. He continued his formation in Paris at the École Nationale des Beaux-Arts under Paul Baudouin, while also working in the studio of Lucien Frédéric Biloul.

Popescu’s international formation secured his acceptance at the Salon des Artistes Français in 1921, affirming his place within the European art scene. Returning to Romania in 1924, he joined the Artistic Youth Society and became an active participant in the interwar exhibitions that shaped modern Romanian art. He exhibited both individually and group shows, as well as at the Official Salon, earning numerous distinctions. A major retrospective of his oeuvre was organised in Bucharest in 1975, attesting to the breadth of his career.

His paintings are characterised by realist portraits and luminous landscapes inspired by his extensive travels across Europe and the Near East. While rooted in Impressionism, his work also integrated elements of Post-Impressionism, with a constant preoccupation with the effects of light. These qualities place Popescu among the important voices of Romanian interwar painting, where the landscape held a central place alongside portraiture and still life.