Even with language barriers, Marčiulionis was a devoted teammate, and active in the communities he played in. In 1987, he helped a Panevėžys man get an artificial heart valve for his son, by appealing to Donnie Nelson, who arranged an operation for the teenager in the United States. In the aftermath of the 1989 San Francisco earthquake, Marčiulionis appeared at the site of a commuter train accident, wearing his Warriors warm up outfit, and he helped by pulling out trapped passengers and administering first aid.