He was a member from Chautauqua County of the New York State Assembly in 1836.

Marvin was elected as a Whig to the 25th and 26th United States Congresses, and served from March 4, 1837 to March 3, 1841.
He was chairman of the Committee on Expenditures in the Post Office Department (26th Congress).

He was a delegate to the New York State Constitutional Convention of 1846.
He was a justice of the New York Supreme Court (8th District) from 1847 to 1871, and was ex officio a judge of the New York Court of Appeals in 1855 and 1863.
Afterwards he resumed the practice of law in Jamestown.
He was a member from Chautauqua County of the New York State Assembly in 1836.
Marvin was elected as a Whig to the 25th and 26th United States Congresses, and served from March 4, 1837 to March 3, 1841. He was chairman of the Committee on Expenditures in the Post Office Department (26th Congress).
He was a delegate to the New York State Constitutional Convention of 1846. He was a justice of the New York Supreme Court (8th District) from 1847 to 1871, and was ex officio a judge of the New York Court of Appeals in 1855 and 1863. Afterwards he resumed the practice of law in Jamestown.
Richard P. Marvin