With his son's aid, Morgan grew his banking house into a trans-Atlantic financial empire that included firms in London, New York City, Philadelphia, and Paris.

At the age of 13, he was enrolled at the American Literary, Scientific, and Military Academy (now Norwich University) in Middletown, Connecticut near the home of his mother's parents.

[1] As was typical for aspiring businessmen of the time, Junius did not enroll in college, but was apprenticed to Alfred Welles, a Boston merchant banker, in 1829.

He remained as a clerk for five years, gaining exposure to the banking industry, as well as a number of mercantile trades in Boston and New York.

He entered business in Connecticut, operating a tavern, coffee house, and stagecoach line,[4] and was a founding partner in the Aetna Fire Insurance Company in 1819.

These prompt payments to the banks destroyed in the fire established Aetna's reputation on Wall Street and allowed the firm to triple its premiums in later years.

The firm gave Morgan access to global markets, exporting and financing cotton and other goods shipped from Boston harbor.

The iron business had drawn the firm into greater involvement in financing American railway construction, including as the initial offeror of bonds for the Ohio and Mississippi Rail Road Company in 1853.

[25] Peabody declined a conditional bailout from the major London houses which would have closed the firm, instead receiving an emergency line of credit of £800,000 from the Bank of England.

[20][26] After the panic and near collapse of Peabody & Co., Morgan became a more cautious investor, demanding statements from all correspondent banks, even at the risk of offending them and even from well-respected former colleagues.

[27][28][29] Despite their own financial difficulties in this period, Peabody and Morgan were chief backers of Cyrus West Field's bedeviled transatlantic cable project throughout.

[30] The firm turned an eventual profit on the venture, but its major purpose was to establish Morgan as a primary backer in the growing communications industry.

[32][33] Though Peabody & Co. made a significant investment in the Transatlantic cotton trade, its principal business was still with correspondent banks in the Eastern United States and with railroad companies.

Working with his son John Pierpont in New York, Morgan was able to receive news of the fall of Vicksburg via telegraph before it became general knowledge in London, buying up Union bonds before their prices rose.

[33] Even so, the bank's position in London may have prevented further profits; buying Union war bonds risked alienating the English textile industry, which was closely aligned with Confederate cotton plantations.

While Philadelphia banker Jay Cooke and those Wall Street banks with German ties made a bonanza during the war, Peabody & Co. had modest profits by comparison.

[39] Morgan was now the wealthiest American banker in London and moved into a Knightsbridge mansion facing the south side of Hyde Park.

When American grain (and consequently rail) prices fell dramatically after the resolution of the Franco-Prussian War, Cooke's heavy investment in the Northern Pacific Railway was no longer sufficient to meet liabilities.

On November 8, a dinner was hosted in his honor at Delmonico's, with Samuel Tilden, John Jacob Astor, and Theodore Roosevelt Sr. among the guests.

[43][36]As Junius took a less active role and Pierpont continued to accrue massive profits, the balance of power within the Morgan empire shifted from London to New York City.

[45] Morgan was "tall with sloping shoulders" and a thickening midriff, a wide face, light blue eyes, a prominent nose, and a firm mouth.

He was generally emotionless, and his friend George Smalley praised his "grave, strong beauty" and his "eyes full of light" but a face that ended in an "immovable jaw.

[58] His sister, Lucy Morgan (d. 1890) was married to Major James Goodwin, one of the founders, and a president for many years, of the Connecticut Mutual Life Insurance Company.

[66][67] At his funeral, the pallbearers were Roland Mather, Levi P. Morton, Anthony Joseph Drexel, Chauncey M. Depew, Cornelius Vanderbilt II, J. C. Rogers, J. Kearney Warren, and Edward John Phelps.