Peabody was born in 1795 in what was then South Danvers (now Peabody), Massachusetts. His family had Puritan ancestors in the state. As one of seven children in a poor family, George suffered some deprivations during his childhood, and was able to attend school for only a few years. He later expressed "I have never forgotten and never can forget the great privations of my early years". These factors influenced his later devotion to both thrift and philanthropy.
In 1816, he moved to Baltimore, where he made his career and would live for the next 20 years. He established his residence and office in the old Henry Fite House, and became a businessman and financier.
At that time London, Amsterdam, Paris and Frankfurt were at the center of international banking and finance. As all international transactions were settled in gold or gold certificates, a developing nation like the United States had to rely upon agents and merchant banks to raise capital through relationships with merchant banking houses in Europe. Only they held the quantity of reserves of capital necessary to extend long-term credit to a developing economy like that of the US.
Peabody first visited England in 1827, seeking to use his firm and his agency to sell American states' bond issues, to raise capital for those states' various programs of "internal improvements" (principally the transportation infrastructure, such as roads, railroads, docks and canals). Over the next decade Peabody made four more trans-Atlantic trips, starting in 1835 and establishing a branch office in Liverpool. Later he established the banking firm of "George Peabody & Company" (later stylised as J.S. Morgan & Co.) in London. In 1837, he took up permanent residence in London, where he lived for the rest of his life.
In the 1840s, the state of Maryland defaulted on its debt and Peabody, having marketed about half of Maryland's securities to individual investors in Europe, became persona non grata around London. The Times of London noted that while Peabody was an "American gentleman of the most unblemished character", the Reform Club had blackballed him for being a citizen of a country that reneged on its debts. At first, Peabody sent letters to scold Baltimore friends about the need for the state to resume interest payment and rewarded reporters with small gratuities for favourable articles about the state.
At last, in 1845 he conspired with Barings to push Maryland into resuming payment by setting up a political slush fund to spread propaganda for debt resumption and elect legislators who would placate their investors. By means of a secret account, the two firms transferred a thousand sterling to Baltimore and even bribed Daniel Webster, the orator and statesman, to make speeches for debt repayment. Their attempts were successful: pro-resumption Whigs were elected and London bankers started to receive payments. Barrings duplicated the same tactics in Pennsylvania. Florida and Mississippi were the most persistent debtors and as such were excluded from Peabody's later philanthropies.
Although Peabody was briefly engaged in 1838 (and later allegedly had a mistress in Brighton, England, who bore him a daughter), he never married. Ron Chernow describes him as "homely", with "a rumpled face ... knobby chin, bulbous nose, side whiskers, and heavy-lidded eyes."
Peabody frequently entertained and provided letters of introduction for American businessmen visiting London, and became known for the Anglo-American dinners he hosted in honor of American diplomats and other worthies, and in celebration of the Fourth of July. In 1851, when the US Congress refused to support the American section at the Great Exhibition at the Crystal Palace, Peabody advanced £3000 (then worth $15,000; worth about $300,0000 in 2015 dollars) to improve the exhibit and uphold the reputation of the United States. In 1854, he offended many of his American guests at a Fourth of July dinner when he chose to toast Queen Victoria before US President Franklin Pierce; Pierce's future successor, James Buchanan, then Ambassador to London, left in a huff. At around this time, Peabody began to suffer from rheumatoid arthritis and gout.
In February 1867, on one of several return visits to the United States, and at the height of his financial success, Peabody was suggested by Francis Preston Blair, an old crony of President Andrew Jackson and an active power in the smoldering Democratic Party as a possible Secretary of the Treasury in the cabinet of President Andrew Johnson. At about the same time, Peabody was also mentioned in newspapers as a future presidential candidate. Peabody described the presidential suggestion as a "kind and complimentary reference", but considered that at age 72, he was too old for either office.
Coat of arms of George Peabody