Patrick Augustus Mervyn Manning was born 17 August 1946, in San Fernando, on the southwest coast of Trinidad. He and his wife have two children; the family adheres to the Anglican sect of Protestantism. Manning was educated at schools in his home town, including the Rose Bank Private School, San Fernando Government School (1953–57), and Presentation College (1958–65). In 1966, he entered the University of the West Indies at Mona, Jamaica, where he studied geology, receiving a bachelor's degree with special honors in 1969. He began working for Texaco Trinidad, Inc. while a student; his first position was as an operator at a refinery. Upon his graduation, he became a geologist for the company, a position he held from 1969–71.
Manning enjoys playing table tennis and chess, as well as reading, in his leisure time.