David was born the third son of Molly and Hezikah Brainerd on April 20, 1718. He was born in Haddom, Connecticut.
David's father was the King's council for the Connecticut colony. His grandfather, Reverand Hobart, on his mothers side, was a pastor in England. David grew up with a heritage of ministers in his family and devotion to the Lord from the time of his birth.
David was one of nine children. Both his mother and father died in 1732, leaving him an orphan. He lived with his sister, Jerusha, from ages 15 to 19. David was known to be a melancholy and sedate young man. He expressed concern for his soul at a very young age.