Asa Gray was born on November 18, 1810, in Sauquoit, New York.

He was a botanist, considered the most important authority of American botany in the 19th century. Although he received a medical degree from Fairfield Medical School in 1831, he decided to devote his life to botanical studies. Harvard University appointed him Fisher Professor of Natural History in 1841, a post he held for over forty years. He was instrumental in unifying the taxonomic knowledge of the plants and his book "Gray's Manual of Botany" (1848) still remains a standard in the field. He was elected to the American Academy of Arts and Sciences and the Royal Swedish Academy of Sciences. In 1864, Gray's donation of 200,000 plant specimens and 2,200 books to Harvard created the botany department and the Gray Herbarium was named after him. He was a pioneer in the study of plant geography. He was an ardent supporter of Darwin’s theories of evolution and "The Origin of Species". He was president of the American Association for the Advancement of Science (1872), the American Academy of Arts and Sciences (1863–1873), and a regent at the Smithsonian Institution (1874–1888). In 1984, the Asa Gray Award was introduced to honor a living botanist for career achievements.

In 1848, he married Jane Lathrop Loring (1821–1909). He died on January 30, 1888, in Cambridge, Massachusetts.