His work in Richmond, Norfolk and the Northern Neck married modern design and planning with local elements like colonial brick and buff-colored mortar.
Like other regional architects such as Virginia Beach's Lewis Rightmier, Richmond's E. Tucker Carlton and Alexandria's Charles M. Goodman, McCullough took the open plans, striking geometry and low profiles of houses by Frank Lloyd Wright and built houses with regional elements appropriate to Virginia's climate and history.
McCullough's trademark features includes terrazzo floors and raised fireplaces with levitating hearths.
[1] McCullough also designed buildings for C&P Telephone, United Virginia Bank and The Tides Inn.
McCullough retired in 1972 to Lancaster County, Virginia in the Northern Neck, and continued to work.