During the prosperous period of Lambton Mills (1850 - 1915), Lambton House was surrounded by large grist mills, saw mills, woolen mills and the local Post Office. The Lambton House was the centre of social activity for the area as well as serving as a station on the stagecoach route on Southern Ontario's main east-west highway. During the early part of the 20th century, Lambton House was a favourite destination for city residents looking for a place to picnic and enjoy a trip to the "country". Lambton House survived the devastating fire of 1915 that destroyed the surrounding buildings, saved by the fact that it was the sole brick building in the area. During Hurricane Hazel, Lambton House served as a staging point for rescue efforts.

The building was designated as an historical site by the City of York in 1985 and the plaque dedicated on the site during the York Bicentennial celebrations in 1993. Restoration began in 1991, with funding from the Province, the City and Heritage York. The exterior was completed in early 1994. Phase II, the main floor interior, was completed in 1998. Phase III, the second floor, was completed in 2002.

In 2010, the front porch was rebuilt.