In 1757, through a recommendation of Lord Bute,[4] he was appointed architectural tutor to the Prince of Wales, later George III, and in 1766 also, along with Robert Adam, Architect to the King, (this being an unofficial title, rather than an actual salaried post with the Office of Works).

[5] He worked for Augusta, Dowager Princess of Wales, making fanciful garden buildings at Kew, and in 1757 he published a book of Chinese designs which had a significant influence on contemporary taste.

[7] His influence was also transmitted through a host of younger architects trained as pupils in his office, including Thomas Hardwick (1752–1825), who helped him build Somerset House and who wrote his biography.

When a scheme to unite a number of government offices on the site of Somerset House in the Strand was projected, his position did not give him automatic authority over the construction; however when William Robinson, secretary to the board, who had been put in charge of the new building, died in 1775, Chambers became its architect.

His initial plans for a great oval courtyard, connected to three smaller, narrow rectangular courts, were soon modified into a simpler rectilinear scheme.

Aged 74.One of Chambers friends, James Maule, wrote in his journal in August 1771: I visited the Stock Exchange and met John Wilson.