This work was an exposition of an ideal constitution, a utopia, designed to facilitate the development of the English republic established after the regicide, the execution of Charles I in 1649.

He was for a time a resident, with his father, in the manor house at Milton Malsor, Northamptonshire, which had been bequeathed by Sir William Samwell to his daughter following her marriage.

The memorial reads, in modern English but punctuated as in the original: "Here under lies the body of Dame Jane, daughter of Sir William Samwell Knight, & late wife to Sir Sapcotes Harington [sic] of Milton Knight, by whom he had issue 2 sons & 3 daughters, viz James, William, Jane, Anne & Elizabeth.

His eighteenth-century biographer, John Toland, says that while there one of his tutors was the royalist High Churchman William Chillingworth, which may have been the case before the latter left for the Catholic seminary in Douai in 1630.

There is some suggestion that he enlisted in a Dutch militia regiment (apparently seeing no service), before touring the Netherlands, Denmark, Germany, France, Switzerland and Italy.

However, while at Hurst Castle Harrington got into a discussion with the Governor and various army officers during which he voiced his support for the King's position concerning the Treaty of Newport, resulting in his dismissal.

[5] The views embodied in Oceana, particularly those bearing on vote by ballot and rotation of magistrates and legislators, Harrington and others (who in 1659 formed a club called the "Rota") endeavoured to push practically, but with little success.

His Works, including the Pakeman Oceana and a previously unpublished but important manuscript A System of Politics, were first edited with a biography by John Toland in 1700.

According to Pocock, Harrington's prose was marred by an undisciplined work habit and a conspicuous "lack of sophistication," never attaining the level of "a great literary stylist."

For example, as contrasted with Hobbes and Milton, "nowhere" to be found are: "important shades of meaning...conveyed [through] rhythm, emphasis and punctuation; ...He wrote hastily, in a baroque and periodic style in which he more than once lost his way.

"[9] By contrast, Rachel Hammersley has argued that Harrington's literary approach was specifically designed to serve his political purposes, to persuade his readers to act on his ideas.

[10] Following the Stuart Restoration, on 25 November 1661 Harrington was arrested on a charge of conspiring against the government in the "Bow Street" cabal[11] and, without a formal trial, was thrown into the Tower.

There, he was "badly treated", and in April 1662 a warrant was issued for him to be held in close custody, which led his sisters into obtaining a writ of habeas corpus.