Löfling was born in Tolvfors Bruk, Gävle, Sweden. He studied at the University of Uppsala where he attended courses taught by Carl Linnaeus. When the Spanish ambassador asked Linnaeus to select a botanist for service in the American colonies, the professor at once named Loefling. He went to Spain in 1751 to learn Spanish, and then embarked with other scientists for South America in February 1754. In Cumana (actual Venezuela) he had entire charge of the department of natural history, and was assisted by two young Spanish doctors. He died in San Antonio de Caroni (Guayana, Venezuela). His death was considered a great loss to natural history, and especially to botany. Linnæus believed the loss irreparable. The manuscripts of Löfling, which were found after his death, were preserved by his two assistants.
Linnæus used the name Loeflingia for the genus of some plants in the Caryophyllaceae family, one species of which grows in Spain and the other in Spanish America.
Parque Löefling in Ciudad Guayana, Venezuela is named after him.
Linnnæus posthumously published his Iter Hispanicum, eller resa til Spanska Länderna uti Europa och America 1751 til 1756 in 1758.
- Wilson, James Grant; Fiske, John, eds. (1888). "Loefling, Peter". Appletons' Cyclopædia of American Biography. New York: D. Appleton.