Spinola was born in Old Field,[2] near Stony Brook, Brookhaven, Suffolk County, Long Island, New York.

[3] He attended Quaker Hill Academy in Dutchess County and then passed the bar exam before establishing a law practice in Brooklyn.

Spinola's brigade led the Union troops on July 23 at the Battle of Wapping Heights in Linden, Virginia, suffering 18 men killed, including two officers.

[5] Following the war, Spinola was a banker and insurance agent and became an influential figure among the rapidly growing Italian immigrant community in the New York City area.

[7] His funeral was held at the Immaculate Conception Church on April 16, 1891, and he was buried at Green-Wood Cemetery in Brooklyn, New York.

1782), later Anglicised as John Leander Spinola,[11] a Portuguese merchant from Madeira Island, and Elizabeth Phelan (1790, Long Island – 1873),[12] daughter of Captain John Phelan (1747, Waterford, Ireland – September 14, 1827, Baltimore, Maryland), who served in the American Revolutionary War, and his wife Susanna Davis (b.

João Leandro Spinola married Eliza Phelan on June 18, 1808, at Trinity Church parish, New York.

[13] Frank W. Alduino, in his book Sons of Garibaldi in Blue and Gray: Italians in the American Civil War (p. 180), refers to his father John as a "prosperous farmer and oysterman" who migrated to the United States from Madeira Island, Portugal, whose family had originally hailed from the city of Genoa, Liguria.

[2][14][15] The Spinolas, of noble Genoese origin, moved into Madeira Island in the late 15th, early 16th century, as merchants.

[18] His grand uncle Phillip Phelan joined the American forces during the Revolutionary War, where he served as lieutenant, and died at the Battle of Eutaw Springs on May 22, 1781.