After having studied philosophy and medicine, he conducted early research on the botany, geology, and anthropology of his country and other parts of North America.
Being poor, he worked in many different jobs to study in the Seminario Tridentino de México, where he devoted himself especially to physics, mathematics, botany, and chemistry.
He traveled more than 3,000 leagues and formed a valuable collection, including a considerable herbarium and a great number of sketches, which he took to Spain in 1803.
In 1816 in Montpellier he met the naturalist Augustin Pyramus de Candolle, to whom he showed the collections he could save, and entrusted to him the manuscripts for a Flora Mexicana.
Pablo de la Llave named the resplendent quetzal Pharomachrus mocinno to honour his mentor Mociño, who was the first to classify the bird.