On March 15, 1955, he was nominated as ambassador to Korea, to succeed
Ellis O. Briggs; previously, he had served as deputy chief of mission in
Manila for several years. Sworn in on March 28, he arrived in
Seoul on May 8. By the end of the week, he had presented his credentials to
Syngman Rhee. His tenure as ambassador was strained, as tensions were high: riots and unrest occurred against the
Neutral Nations Supervisory Commission, as South Koreans considered the commission to be tainted by Communist influence, and demonstrations rocked the
United States Embassy and his residence; the
Eighth Army began tightening restrictions on the black market, which Korean men saw as unfairly targeting them; and foreign businessmen, including Americans, charged that they were being unfairly taxed by the South Korean government; all of which contributed to an inability to work with Rhee. a contrived excuse. (Indeed, after Lacy left, it was noted that U.S. policy at the time seemed specifically tailored to angering Rhee and South Koreans.) ==Later career==