Immigration and career in America
Upon Carey's arrival in Philadelphia, he found that Franklin had recommended him to Gilbert du Motier, Marquis de Lafayette, who gave him a $400 check to establish himself. He used this money to set up a new publishing business and a book shop. he founded:
The Pennsylvania Herald (1785)
Columbian Magazine (1786), and
The American Museum.
None of these ventures proved very profitable. The American Museum was the first American periodical to treat American culture as rich and original, instead of a poor imitation of Great Britain's. Carey printed the first American version of the Douay–Rheims Bible in 48 weekly installments; this Roman Catholic edition is popularly known as the Carey Bible. Subscribers could arrange to have it bound. It was the first Roman Catholic version of the Bible printed in the United States. Carey also printed numerous editions of the King James Version, fundamental to English-speaking peoples.
In 1794–1796, Carey published America's first atlases. His 1802 map of Washington, D.C., was the first to name the stretch of land west of the United States Capitol as the "Mall".
He frequently wrote articles on various social topics, including events during the Yellow Fever Epidemic of 1793, which proved a crisis for the city. Carey reported on debates in the state legislature as well as providing political commentary in his essays. He was a Catholic and a founding member of the American Sunday-School Society, along with Quaker merchant Thomas P. Cope, Benjamin Rush and Episcopal bishop William White.
In December 1798, the leading Federalist paper, the Gazette of the United States, identified Carey as a leading light within the recently formed American Society of United Irishmen, alongside his Market Street neighbor, the publisher of the Jeffersonian paper, Philadelphia Aurora, William Duane, and Theobald Wolfe Tone's confidante in America, James Reynolds. Against the backdrop of America's Quasi War with French and of the Haitian Revolution (then still under the flag of the French Republic), William Cobbett, linked the association of United Irish exiles to the purportedly levelling tendencies of the emerging Democratic-Republican Party, and of conspiring with Paris to organise slave revolts and "thus involve the whole country in rebellion and bloodshed".
Carey had refused to publish Cobbett's Observations on the Emigration of Dr. Joseph Priestly. Priestley, the founder in England of the Unitarian Church, was also accused by Cobbett of French-inspired revolutionary subversion.
In 1822 Carey published Essays on Political Economy; or, The Most Certain Means of Promoting the Wealth, Power, Resources, and Happiness of Nations, Applied Particularly to the United States. This was one of the first treatises favoring Alexander Hamilton's protectionist economic policy.
During Carey's lifetime, the publishing firm evolved to M. Carey & Son (1817–1821), M. Carey & Sons (1821–1824), and then to Carey & Lea (1824). Carey retired in 1825, leaving the publishing business to his son, Henry Charles Carey and son-in-law Isaac Lea.
Lea and Henry Carey made the business economically successful and, for a time, it was one of the most prominent publishers in the country. The business published such works as: The Encyclopedia Americana, a dictionary of German lexicon, as well as American editions of the works of authors Sir Walter Scott and James Fenimore Cooper.