Percival James (known as P.J.) Patterson was born in 1935. His father was a farmer and his mother a primary school teacher. Patterson was educated at Somerton Primary School and won a scholarship to attend Calabar High School. He graduated in 1953 and went on to the University of the West Indies (UWI), earning a Bachelor of Arts degree (with honors) in English in 1959. He studied law at the London School of Economics, where he was awarded the Leverhume Scholarship and the Sir Hughes Parry prize for excellence in the law of contracts. He graduated from the London School of Economics in 1963 with a bachelor of law degree. Upon completion of his studies, Patterson was called to the Middle Temple and Jamaican Bars. He is divorced and has two children.
Patterson's political activity began at the UWI, where he was a founding member of the Political Club. As president, he presided over the first political address given in the Caribbean by the late Eric Williams, a scholar, regionalist, and founder of the Trinidad and Tobago's People's National Movement (PNM). In 1955, he made further contacts with prominent leaders of the PNM and made his first appearance on a political platform during an election campaign. On graduating from UWI, he joined the PNP's organizing staff, serving a number of rural parishes.