Williams moved to China in 1833 to run a printing press for foreign missions.
In 1853 he was assigned to Perry’s expedition to Japan as an interpreter.
Although he was fluent in Mandarin Chinese, he had little experience with the Japanese language.
He also collected plant specimens for the expedition.
Williams kept a journal which is thought to be the best private published account of the expedition.
In 1877, he returned to the United States
where he became the first professor of Chinese language and literature at Yale University.