Among the handful of American saints, St. Damien of Molokai is best known for his work in a leper colony in Hawaii.
The Vatican biography gives a good summary of his life.
Furthermore, "At his own request and that of the lepers, he remained on Molokai. Having contracted leprosy himself, he died on April 15, 1889, at the age of 49, after serving 16 years among the lepers."
St. Damian was known for his heroic faithfulness to the people he served, unwilling to leave the island even in the face of contracting the disease.
His example of selfless service has inspired many over the years, and is an example of a missionary who cared more about the people he served than for himself and his needs.