Afterwards he studied law in the offices of Erastus Root and Amasa J. Parker, was admitted to the bar in October 1832.

In 1843, he was appointed master in chancery and then entered a law partnership with David Codwise.

He joined the Republican Party when it was founded, and was a member of the New York State Assembly (Chemung Co.) in 1860 and 1861.

[2] Robinson was a delegate to the 1876 Democratic National Convention and supported Samuel J. Tilden for president.

While serving as comptroller, he was elected governor, defeating Edwin D. Morgan by nearly a 40,000 majority.

He was in office from 1877 to 1879, the first governor to serve a three-year term after the amendment to the state constitution in 1874.

This happened, and the Republican candidate Alonzo B. Cornell was elected governor with fewer votes than Robinson and Kelly together.