Over the next two decades, Seamster practiced law and served as Chancery Judge of the 13th District for eighteen years before representing the Fayetteville area in the Arkansas House from 1947 to 1948.

He earned his teaching license at age 17,[3] and taught in a rural Benton County school for two years while saving money for further education.

[1] He was elected mayor of Bentonville in 1921, but resigned the following November to move to Fayetteville and open a law practice with partner John W.

[9] Seamster also maintained a farm in Benton County, and was a member of several prominent social organizations, including the Independent Order of Odd Fellows, Freemasonry, and the Knights of Pythias, where he served as Chancellor Commander.

[6] During his tenure, Seamster adjudicated thousands of cases, including many involving financial institutions, highways, and business transactions between farmers and ranchers.

The cases represented a microcosm of the larger issues plaguing the state at the time, which often saw banks run insolvent and did not have a highway fund.

[11][12] Seamster elected against running, instead managing Dwight H. Blackwood's failed campaign for the Democratic gubernatorial nomination.

[13] Ultimately, Junius Marion Futrell of Northeast Arkansas, a longtime chancery judge and former state representative in his own right, won the Democratic nomination and 1932 election.

[14] Following the death of Arkansas Supreme Court Associate Justice Turner Butler in 1938, rumors of Governor's Carl E. Bailey appointment to fill the position crossed the state.

Political friends in the Democratic party were the heavy favorite, including Seamster, and even Bailey himself resigning as governor to take the position.

[16] In 1947, he was extremely well respected in the legal and political communities, described as "one of the most capable attorneys in the State of Arkansas" and "Mr. Seamster possesses a stateman's grasp of affairs and ever keeps pace with the best thinking men of the age".

Davis published an affidavit in The Northwest Arkansas Times detailing a conversation he had with Jim Gregory, a prominent Fayetteville resident, shortly after announcing his reelection campaign.

[21] Seamster was appointed to his former position as chancery judge by Governor Sid McMath on August 30, 1949, following news that John K. Butts was killed in a car accident.

[22] The Seamsters hosted several events at Country Gardens, frequently covered by the society pages of the local newspapers.