From 1920 to 1926 he was attached to the College of Agriculture in U.P., and from 1926 to 1928 to the University of California; in 1928 appointed systematic botanist and since February 1934 acting chief of the Natural Museum Division of the Bureau of Science, Manila, now director of the National Museum.

When assigned to the U.S. Navy in Guiuan, at the southern tip of Samar, made collections in that region.

Quisumbing undertook restoration of the Herbarium, which was completely destroyed during the war.

Quisumbing was author of taxonomic and morphological papers, many of which deal with orchids, including ‘Medicinal plants in the Philippines’ (Manila 1951).

He was recipient of the Distinguished Service Star (1954) for outstanding contribution to the field of systematic botany; Diploma of Merit on Orchidology and Fellow Gold Medal, Malaysian Orchid Society (1966); Gold Medal, American Orchid Society (1969),[1] and 1975 PhilAAS Most Outstanding Award.