He attended Peekskill Military Academy and Charlottesville University Mechanics Institute, and then became a carpenter.
During the American Civil War, he fought with the 71st New York Volunteers.
After the war he engaged in the manufacture of stoves in Peekskill.
Robertson was a member of the New York State Assembly (Westchester Co., 3rd D.) in 1882.
He died on September 17, 1906, at his home in Peekskill, New York, "after a long illness, from paralysis", and was buried at the Hillside Cemetery in Cortlandt Manor.