[4] Lichauco traveled throughout the United States delivering speeches to promote the idea of Philippine independence.
He collaborated with Moorfield Storey to publish "The Conquest of the Philippines by the United States," which drew attention to the Philippine-American war.
In the 1930s, Lichauco was secretary to the OsRox Mission, which traveled to the United States Congress to urge passage of a bill granting independence to the Philippines.
After the war, Lichauco published his memoir "Dear Mother Putnam" to document day-to-day life in Japanese-occupied Manila.
[5] In 1963, President Diosdado Macapagal appointed Marcial Lichauco as Philippine Ambassador to the United Kingdom, Denmark, Norway and Sweden.