Born in Huşi into a modest family, he completed his primary and secondary studies in his hometown. In 1902, deciding to follow his passion for music, he left for Iaşi, where he took cello classes at the Iaşi Conservatory. In summer of 1903, Dimitrescu entered the National School of Fine Arts in the city, studying in the same class as Nicolae Tonitza; the two studied under Gheorghe Popovici and Emanoil Bardasare. After graduation, Dimitrescu painted murals for the Orthodox churches in Agăş and Asău (Bacău County). Between 1912 and 1913, he studied in Paris, at the Académie de la Grande Chaumière, during which time he was attracted to Impressionism.
Drafted into the Romanian Army at the start of the Romanian Campaign of World War I, Dimitrescu was profoundly touched by the experience, and began painting tragic pieces that documented the misery brought by the conflict. Like his friend Tonitza, he began exploring social themes, such as queuing and the effects of bombardments.
Peasant women from Sălişte
In 1917, along with the painters Camil Ressu, Iosif Iser, Marius Bunescu and the sculptors Dimitrie Paciurea, Cornel Medrea, Ion Jalea and Oscar Han, he founded the Art of Romania association in their Iaşi refuge. In 1926, Dimitrescu, with Oscar Han, Francisc Şirato, and Nicolae Tonitza, established Grupul celor patru ("The Group of Four").
Turks in Mangalia
He became a teacher at the Iaşi National School of Fine Arts in 1927, and, during the next year, he was named its headmaster (a position he held until his death). Towards the end of his life, Dimitrescu began expanding his palette to cover more somber colors, while exploring compositions in which the background was stripped of details and usually of a dominant white.
Landscape from Mangalia
Most of Dimitrescu's paintings take inspiration mainly from the life of simple folk, and especially from that of Romanian peasants and miners; they attempt to portray Romanian traditions and way of life, drawing on his encounters with both Byzantine art and the work of Paul Cézanne.
Women on the beach
Part of his art (between 1926 and 1933) was inspired by his travels to Dobruja, and have been considered to be the most accomplished synthesis between his craft as a draftsman and his art as a painter.
Peasant women working at a loom
Many of his works are exhibited in Bârlad (at the Vasile Pârvan Museum), Bucharest (the National Museum of Art of Romania and the Zambaccian Museum), Cluj-Napoca (Cluj Art Museum) and in private collections outside Romania (in Austria, Belgium, France and Germany).