João Manuel de Almada e Melo was born in Troviscoso, Monção, on 15 August 1703. He was the son of Brigadier António José de Almada e Melo, Lord of Vila Nova de Souto de El-rei, mayor of Palmela and majorat of Olivais, and of Maria Josefa de Lima da Cunha Velho, son of the Governor of Monção, Francisco da Cunha da Silva. He was the brother of Maria Luísa Engrácia de Mendonça, Francisco de Almada e Mendonça, 1st Viscount of Vila Nova de Souto de El-rei, and Alexandre de Sousa de Almada. He was baptised in the parish of Santa Maria dos Anjos on 3 September, and was the godson of master D. João Manuel de Noronha.
João de Almada e Melo was the 7th Lord of the Majorat of Olivais, 11th Lord of Albergaria da Madalena and 1st Squire, 8th Mayor of Palmela, counsellor of the king, Commander of Christ, nobleman of the Royal Court, and Governor of Justice and High Court of Porto.
He joined the army at the age of 15 in Viana. In 1735, he rose to the rank of Captain and was sent to the garrison in Portalegre. He was also stationed at Monção and Elvas, and in 1745 he was promoted to Colonel in the regiment of Cascais.
It is thought that the first news of his connection to Porto dates to 29 June 1735, after which he visited the city several times.
At the age of 49 he married Ana Joaquina de Lencastre, the widow of Gonçalves de Almeida de Sousa e Sá, and mother of 12 or 13 children. The wedding took place at her house in Quinta do Paço, Valadares, Vila Nova de Gaia. They had two children, António José de Almada e Melo (1753-1789), the future 2nd Viscount of Vila Nova de Souto de El-rei, and Francisco de Almada e Mendonça, who became magistrate and ombudsman of the county of Porto.
João de Almada e Melo was in Lisbon in 1755 when the earthquake happened, and he was responsible for guarding king José I in the Royal Palace. In 1757, after the popular uprising in Porto he settled in this town, in the Palace of the Corpo da Guarda, as the Governor of Arms.
During the following years (1758-1761), he was Brigadier, Chairman of the Board of the Navy of Porto, military governor of the provinces of Minho and Trás-os-Montes, Chairman of the Board of Public Works (1763-1786), Governor of Justice and Court of Porto (1765-1786) and Director of the Public Repository of Porto (1774). He excelled at the Public Works office, where he developed a policy to modernise the city of Lisbon, opening and renewing several roads, building public works, contributing to the establishment of a new architectural model and of the norms governing the licenses for private construction works.
A military and politician, Almada e Melo was also dedicated to culture and teaching. He is considered the introducer of the lyric theatre in Portugal because of his performance at the Teatro do Corpo da Guarda, active between 1760 and 1797. He is thought to have been connected to the Arcádia Lusitana Portuense.
As the Chairman of the Board of the Navy, João de Almada e Melo played a decisive role in creating the Nautical Class.
He implemented the project of Sebastião José de Carvalho e Melo in the north of Portugal, and was loyal to him even after the death of the king, in 1777.
He died on 3 October 1786 and was buried in the family’s tomb in the chapel of Senhora de Rosa, in the church of Monção.