He was the author of a number of scholarly Jewish works, including a commentary on Talmud Yerushalmi (the Jerusalem Talmud) and his 7 volume magnum opus The Legends of the Jews, which combined hundreds of legends and parables from a lifetime of midrash research.
Professor Ginzberg wrote some 450 articles for the Jewish Encyclopedia, some later collected in his Legend and Lore. He was an important halakhic authority of the Conservative movement in North America; for a period of ten years (1917-1927), he was virtually the halakhic authority of this movement. He was also founder and president of the American Academy of Jewish Research.
Many of his papers are collected in The Responsa of Professor Louis Ginzberg, Ed. David Golinkin, JTS, 1996.