George Knowles was born in Yorkshire, England about 1776. He worked both as a designer and contractor. He worked in Ireland from about 1800 to 1820 during which time he was the contractor for the Richmond Bridge (1812 - 1816, now O’Donovan Rossa) over the River Liffey and the next bridge upstream, Whitworth Bridge (1816 - 1817, now Father Mathew). He agreed to build the latter bridge for the same cost as the first. Knowles worked on a number of projects (including these bridges) with fellow designer James Savage. Knowles also built Lucan Bridge in 1814 and this bridge is still the longest single span masonry arch bridge (33.83m / 111 ft) in Ireland. Its design is much admired and bears some similarities to Island Bridge downriver of it.
Knowles returned to England and was involved in the building of St. John’s Church, Sharow, Yorkshire in 1825. He continued to work around Scarborough for the remainder of his life. He died there in 1856.