Robert Stansbury Johnston was born on July 7, 1926 to Robert McCutcheon and Alice Johnston who lived in Elizabeth, New Jersey. Robert was one of three children. 

The family eventually moved to Downingtown, where Robert registered for the draft. He entered service in the Army on October 3, 1944 and was assigned to the 172nd Infantry Regiment, 43rd division.  

On January 9, 1945, the 43rd made an assault landing in the San Fabian area, Lingayen Gulf, Luzon. Under enemy fire, the division secured the beachhead and fought into the Lingayen Plain by February 12th. The offensive was resumed against the enemy north and west of Fort Stotsenburg, on February 27th. After ending Japanese resistance in the Zambales Mountains with help from the Philippine Commonwealth Army and Philippine Constabulary, the 43rd swung south against the Shimbu Line. On May 6, 1945, the attack continued in the Bulacan area. IPO Dam was secured and enemy opposition smashed in the area, on May 19. Mopping-up activities continued until June 30, 1945.

Private Robert Stansbury Johnston was killed in action on March 4, 1945, in the Philippines. 

Robert is buried at the Manila American Cemetery in the Philippines.