Abbott was born in Forestville, New York, to George Burwell Abbott (May 1858 Erie County, New York – February 4, 1942 Hamburg, New York) and Hannah May McLaury (1869 – June 20, 1940 Hamburg, New York). He later moved to the town of Salamanca, which twice elected his father mayor. In 1898, his family moved to Cheyenne, Wyoming, where he attended Kearney Military Academy. Within a few years, his family returned to New York, and he graduated from Hamburg High School in 1907. Four years later, he obtained a Bachelor of Arts degree from the University of Rochester, where he wrote his first play, Perfectly Harmless, for the University Dramatic Club. Abbott then attended Harvard University, to take a course in playwriting from George Pierce Baker. Under Baker's tutelage, he wrote The Head of the Family, which was performed at the Harvard Dramatic Club in 1912. He then worked for a year as "author, gofer, and actor" at the Bijou Theatre in Boston, where his play The Man in the Manhole won a contest.