[3][4] In 1817, Coolidge graduated from Harvard College, along with classmates George Bancroft, Caleb Cushing, and Samuel A. Eliot.

[2] Coolidge visited Monticello in the spring of that year for two weeks, during which he met Ellen Wayles Randolph.

[6] In January 1827, or earlier, Coolidge had recommended that Jefferson's manuscripts should be published with Jared Sparks' assistance.

[2] While Coolidge headed the Augustine Heard and Company in Canton, Ellen lived for two years in Macao.

[10] After starting his career as a clerk, by 1834 he had become a working partner with Russell & Company,[2][11] which was "probably the most important American seller" of Indian opium.

By the 1830s, Russell & Company had nearly all of the American trade in Chinese opium, but by 1833 lost its lead due to mismanagement.

[10] Coolidge was overwhelmed with the influx of new business and asked Augustine Heard to sail to China to help manage the significant growth.

He spent two days in a Chinese prison and was saved by factory workers who declared that he was not British, but an American man.

The factory was destroyed and Coolidge filed an excessively high claim for punitive and compensatory damages.