Rejecting his family's hope that he would enter the fur trade at Albany or mercantile pursuits in New York City, young Livingston chose to pursue a career in law at the latter place. Before he completed his legal studies, in 1745 he married Susanna French, daughter of a well-to-do New Jersey landowner. She was to bear 13 children.

Three years later, Livingston was admitted to the bar and quickly gained a reputation as the supporter of popular causes against the more conservative factions in the city. Associated with the Calvinists in religion, he opposed the dominant Anglican leaders in the colony and wielded a sharply satirical pen in verses and broadsides. Livingston attacked the Anglican attempt to charter and control King's College (later Columbia College and University) and the dominant De Lancey party for its Anglican sympathies, and by 1758 rose to the leadership of his faction. For a decade, it controlled the colonial assembly and fought against parliamentary interference in the colony's affairs. During this time, 1759-61, Livingston sat in the assembly.

In 1769 Livingston's supporters, split by the growing debate as to how to respond to British taxation of the colonies, lost control of the assembly. Not long thereafter, Livingston, who had also grown tired of legal practice, moved to the Elizabethtown (present Elizabeth), NJ, area, where he had purchased land in 1760. There, in 1772-73, he built the estate, Liberty Hall, continued to write verse, and planned to live the life of a gentleman farmer.

The Revolutionary upsurge, however, brought Livingston out of retirement. He soon became a member of the Essex County, NJ, committee of correspondence; in 1774 a representative in the First Continental Congress; and in 1775-76 a delegate to the Second Continental Congress. In June 1776 he left Congress to command the New Jersey militia as a brigadier general and held this post until he was elected later in the year as the first governor of the state.

Livingston held the position throughout and beyond the war--in fact, for 14 consecutive years until his death in 1790. During his administration, the government was organized, the war won, and New Jersey launched on her path as a sovereign state. Although the pressure of affairs often prevented it, he enjoyed his estate whenever possible, conducted agricultural experiments, and became a member of the Philadelphia Society for Promoting Agriculture. He was also active in the antislavery movement.

In 1787 Livingston was selected as a delegate to the Constitutional Convention, though his gubernatorial duties prevented him from attending every session. He did not arrive until June 5 and missed several weeks in July, but he performed vital committee work, particularly as chairman of the one that reached a compromise on the issue of slavery. He also supported the New Jersey Plan. In addition, he spurred New Jersey's rapid ratification of the Constitution (1787). The next year, Yale awarded him an honorary doctor of laws degree.

Livingston died at Liberty Hall in his 67th year in 1790. He was originally buried at the local Presbyterian Churchyard, but a year later his remains were moved to a vault his son owned at Trinity Churchyard in Manhattan and in 1844 were again relocated, to Brooklyn's Greenwood Cemetery.