His career began with The Skylark of Space (serialized in Amazing Stories in 1928), one of the first novels to depict interstellar travel. This launched the popular Skylark series, followed by Skylark Three (1930), Skylark of Valeron (1934), and Skylark DuQuesne (1965).
Smith's most influential achievement is the Lensman series, an epic saga chronicling a cosmic war between civilizations. It comprises Triplanetary (1948), First Lensman (1950), Galactic Patrol (1950), Grey Lensman (1951), Second Stage Lensman (1953), and Children of the Lens (1954). The series expanded the imaginative scale of science fiction and profoundly influenced later writers, including Robert A. Heinlein and Arthur C. Clarke.
Honored with the First Fandom Hall of Fame Award and the Gandalf Grand Master Award, Smith remains a foundational figure whose grand cosmic visions and heroic narratives helped define the golden age of science fiction.