Self-sacrificing

Audubon was blessed with good health, length of years, a devoted and self-sacrificing wife, and a buoyant, sanguine, and elastic disposition. He had the heavenly gift of enthusiasm—a passionate love for the work he set out to do. He was a natural hunter, roamer, woodsman; as unworldly as a child, and as simple and transparent. We have had better trained and more scientific ornithologists since his day, but none with his abandon and poetic fervour in the study of our birds.

Source: tatoeba (12181586)

Mother Teresa's self-sacrificing nature made her world-famous.

Source: wiktionary

It [Troutbeck] has religious isolation also, for it is several miles—and very strenuous miles in winter—from the parish church at Mungrisdale, and the introduction of the harmonium to the waiting room was due to the zeal of a vicar of many years ago who, in the absence of any other room in the village, obtained permission to use the premises for services, including Sunday School. Most of his successors have continued this self-sacrificing duty.

Source: wiktionary