In February 1838, Graves was appointed justice of the peace by Governor Henry Dodge. He went on to serve more than a decade in that role. During those years he was also elected to the Walworth County board of supervisors and the House of Representatives of the Wisconsin Territory, running on the Democratic Party ticket. When Wisconsin achieved statehood in 1848, Graves was elected to the first session of the Wisconsin State Assembly as the representative of Walworth County's 1st Assembly district—then-comprising the northeast corner of the county.
