He was born in Auburn, New York where he attended the public schools.

Lockhart was the city clerk in 1836 and 1837 and the prosecuting attorney of Vanderburg County, Indiana 1841–1845.

After leaving Congress, he resumed the practice of his profession in Evansville, Indiana.

He was appointed by President Franklin Pierce superintendent of construction of the marine hospital at Evansville in 1853.

He was elected to the Thirty-fifth Congress and served from March 4, 1857, until his death in Evansville, Indiana on September 7, 1857.