Born Marceline Newlin in Colorado Springs, Colorado and raised in Salt Lake City, Utah, she was the younger sister of film actress Alice Day.
Marceline Day began her film career after her sister, Alice Day, became a featured actress as a Mack Sennett "Bathing Beauty" in one and two-
In 1926, Marceline Day was named one of the thirteen WAMPAS Baby Stars, a promotional campaign sponsored by the Western Association of Motion Picture Advertisers in the United States, which honored thirteen young women each year who they believed to be on the threshold of movie stardom. Other notable recipients that year were Joan Crawford, Mary Astor, Janet Gaynor and Dolores del Río. The publicity from the campaign added to Day's popularity and in 1927 she appeared opposite John Barrymore in the romantic adventure The Beloved Rogue.
Marceline Day is probably best recalled for her appearances in the 1928 comedy The Cameraman opposite Buster Keaton, and the 1929 drama The Jazz Age opposite Douglas Fairbanks. By the late 1920s, Day's career had eclipsed her sister Alice's, who herself was quite a publicly popular actress. The two would appear together onscreen again in the 1929 musical The Show of Shows.