Carlyle's reputation suffered a blow in the 1850s after publishing a series of Latter-Day Pamphlets, offering controversial political views on former slaves, the Irish and corporal punishment at odds with prevailing opinion. He also lost friends, including John Stuart Mill. His good name was only fully restored in old age, as he became known as the Sage of Chelsea.

He began Frederick the Great in 1852, a project that would occupy him over the next 13 years as his tolerance of any kind of noise decreased. Jane was increasingly ill, although she appeared well enough for Carlyle to agree in 1866 to travel to Edinburgh University to take up the honourary post of Lord Rector. She was found dead in her carriage before his return, leaving Carlyle grief-stricken. He resolved to edit and preserve her letters and diaries.

Soon he was forced to dictate his work, due to an increasingly shaky right hand. He accepted a Prussian Order of Merit from Bismarck in 1874, but refuses a baronetcy offered by Disraeli. In 1888 he died and was buried beside his brother in Ecclefechan churchyard.