White had no formal architectural training; he began his career at the age of 18 as the principal assistant to Henry Hobson Richardson, the greatest American architect of the day and creator of a style recognized today as "Richardsonian Romanesque". He remained with Richardson for six years.[2] In 1878, White embarked for a year and a half in Europe, and when he returned to New York in September 1879, he joined Charles Follen McKim and William Rutherford
Mead to form McKim, Mead and White. As part of the partnership, all commissions designed by the architects were identified as being the work of the collective firm, not any individual architect.[2]
In 1884, White married 22-year-old Bessie Springs Smith. His new wife hailed from a socially prominent Long Island family; her ancestors were early settlers of the area, and Smithtown, New York, was named for them. Their estate, Box Hill, was not only a home, but also a showplace illustrating the luxe design aesthetic White offered prospective wealthy clients. A son, Lawrence Grant White, was born in 1887.[3]