Son of a poet, Ramsay attended the Academy of Saint Luke in Edinburgh. After moving to London to study with Hans Hysing in 1732, he returned to Edinburgh the following year. He first visited Italy in 1736-8, where he studied with Imperiali and at the French Academy in Rome. In 1738 he set up as a portrait painter in London where he soon attracted a distinguished clientele. His work during this period was notable for its directness and candour, revealing the influence of his contemporary Hogarth. In the 1750s his style became more elegant, recalling contemporary French painting. In 1773 Ramsay fell from a ladder, crippling his right arm, and retired from painting. He visited Italy again in 1775-7 and 1782, and died on his way back to London in 1784.