Born in Jacksonville to Isaiah Hart, one of the city's founders, he was raised on his father's plantation along the St. Johns River.

He moved to a farm near Fort Pierce, Florida in 1843, and was a founding member of the St. Lucie County Board of Commissioners.

Among his clients was "Adam", a black man who was lynched after the Florida Supreme Court declared his murder conviction a mistrial.

[2]: 269 Despite his upbringing, Hart became a Republican and openly opposed secession from the United States, causing some difficult times for him during the American Civil War.

During his tenure, "limited civil rights legislation was passed, and some improvements were made in the state's weakened finances.