In 1866, the journalist William Jerdan wrote that "From Marco Polo to Mungo Park, no three of the most famous travellers, grouped together, would exceed the extent and variety of countries traversed by our blind countryman."

This position demanded he attend church service twice daily as his only duty in return for room and board, but the quietness of such a life harmonized so poorly with his active habits and keen interests, physically making him ill, that he requested multiple leaves of absence on health grounds, first to study medicine and literature at the University of Edinburgh, then to go abroad on a Grand Tour from 1819 to 1821 when he journeyed through France, Italy, Switzerland, the parts of Germany bordering on the Rhine, Belgium and the Netherlands.

There he was suspected by the Czar of being a spy who might publicize the extensive activities of the Russian American Company should he travel further east, and was conducted back forcibly to the frontiers of Poland.

Shortly afterwards he again set out to accomplish by a somewhat different method the design which had been frustrated by the Russian authorities; and an account of his remarkable achievement was published in four volumes in 1834–1835, under the title of A Voyage Round the World, including Travels in Africa, Asia, Australasia, America, etc., from 1827 to 1832.

On Fernando Po Island, now part of Equatorial Guinea, the British Government named the Holman River in his honour, commemorating his contributions to fighting the slave trade in the region during the 1820s.