Kotin served in the U.S. Army military service during World War II (1941–1945).
After the war Kotin found a studio on 10th Street. He soon joined the "Downtown Group" which represented a group of artists who found studios in lower Manhattan in the area bounded by 8th and 12th street between First and Sixth Avenues during the late 1940s and early 1950s. These artists were called the "Downtown Group" as opposed to the "Uptown Group" established during the war at The Art of This Century Gallery. In 1949 Kotin joined the "Artists' Club"located at 39 East 8th Street. Albert Kotin was chosen by his fellow artists to show in the Ninth Street Show held on May 21 – June 10, 1951.The show was located at 60 East 9th Street on the first floor and the basement of a building which was about to be demolished. "The artists celebrated not only the appearance of the dealers, collectors and museum people on the 9th Street, and the consequent exposure of their work but they celebrated the creation and the strength of a living community of significant dimensions." Wikipedia