The Geoghegan family, originally from Dublin moved to London in 1756, where they changed their name to Gahagan. At first, Lawrence Gahagan met with little success, but eventually won first prize at the Society of Arts in 1777, for his medallion depiction of Alexander exhorting his Troops. His later bronzes included busts of Nelson, Wellington, Czar Alexander I and Blucher.
Lawrence's brothers, Sebastian and Vincent, as well as his sons and daughters, Charles, Edwin, Lucius and Sarah, were all sculptors in their own right and indeed, it has been suggested that many of Lawrence's portrait busts were actually sculpted by his son Lucius.