Ross was elected as a Republican to the Eleventh Congress. He was again elected to the Fourteenth and Fifteenth Congresses. He resigned in 1818 to become president judge of the seventh judicial district of the State. He was transferred to the State supreme bench in 1830 and served until his death.
Ross was married to Mary Ross (1774–1845); they were the parents of Thomas Ross, another congressman. He was buried in a private cemetery on the family estate, "Ross Common Manor", Ross Township, Pennsylvania. He was buried next to his wife.