The third-born child and only surviving son of Justina Brandly Lazarus and Joshua Isaacs, Jr., Solomon Isaacs was born and raised in New York City, where his father was a leading member of Congregation Shearith Israel.

After his older sister Frances married copper trader Harmon Hendricks in June 1800, 14-year-old Solomon was brought into the burgeoning business as an apprentice. He proved himself more than capable, and on successfully completing the terms of his apprenticeship in 1807 was entrusted by Hendricks with the appraisal and purchasing of copper at public auction. Within a year and a half of this assignment, Isaacs was promoted by Hendricks to the role of an independent commission merchant. A few years later, when Hendricks determined to move into copper production by purchasing and reinvigorating the inactive Soho copperworks in Belleville, New Jersey, Isaacs was chosen to oversee the operations of the mill, with full authority for its administration. Isaacs was also made fullpartner with Hendricks in the new manufacturing venture, which operated independently from Hendricks’ copper trading business. In the capacity of mill manager, Isaacs was in frequent contact with clients of the firm, which included Paul Revere and Robert Fulton. Isaacs quickly became known as “Steamboat Isaacs” in Jewish circles, after the copper boilers the mill produced for Fulton’s steamboats. Isaacs was also responsible for training a number of younger relations in the manufacture of copper, including his two young nephews, Uriah and Henry Hendricks. By mutual agreement, Hendricks and Isaacs dissolved their partnership in 1827, and the business was reconstituted under the leadership of Uriah and Henry. Isaacs maintained a minority share for another three years, but when that partnership expired in April 1830, he struck out on his own as a copper broker.

Isaacs eschewed marriage during his 20s and 30s, choosing instead to focus his energies on the copper business. While he maintained living quarters at the Soho mill during this period so as to keep an eye on its operations, he was a frequent visitor to his sister’s home and doted on his numerous nieces and nephews. However, in his early forties, he had a change of heart. In 1829, at age 44, he married 24-year-old Elkalah Kursheedt, eldest daughter of the scholar Israel Baer Kursheedt. The marriage prompted a move back to New York, where Isaacs followed in his father’s footsteps and became active in congregational affairs at Shearith Israel. Despite his late start, Isaacs would eventually father ten children, the last born just four years before his own death at age 69.