At the age of nineteen, he inherited a farm near Durham, but returned to East Haddam a year later to prepare to enter Yale.

On July 12, 1739, he recorded having an experience of "unspeakable glory" that prompted in him a "hearty desire to exalt [God], to set him on the throne and to 'seek first his Kingdom'".

[5][6] A recent law forbade the appointment of ministers in Connecticut unless they had graduated from Harvard, Yale, or a European institution, so Brainerd had to reconsider his plans.

As a result, he gained the attention of Jonathan Dickinson, the leading Presbyterian in New Jersey, who unsuccessfully attempted to reinstate Brainerd at Yale.

Instead, Dickinson suggested that Brainerd devote himself to missionary work among the Native Americans, supported by the Society in Scotland for Propagating Christian Knowledge.

[8] On April 1, 1743, after a brief period serving a church on Long Island, Brainerd began working as a missionary to Native Americans, which he would continue until late 1746 when he became too ill.

He continued his work converting Native Americans, writing in his diary: '[I] could have no freedom in the thought of any other circumstances or business in life: All my desire was the conversion of the heathen, and all my hope was in God: God does not suffer me to please or comfort myself with hopes of seeing friends, returning to my dear acquaintance, and enjoying worldly comforts'.

In his diary entry for September 24, Brainerd wrote: 'In the greatest distress that ever I endured having an uncommon kind of hiccough; which either strangled me or threw me into a straining to vomit'.

[18][19] It gained immediate recognition, with eighteenth-century theologian John Wesley urging: 'Let every preacher read carefully over the Life of David Brainerd'.

[21]Other missionaries who have asserted the influence of Jonathan Edwards's biography of Brainerd on their lives include Henry Martyn, William Carey, Jim Elliot,[22] and Adoniram Judson.