Dimmick was elected as a Democrat to the Thirty-first and Thirty-second Congresses. While a member of congress, he served a chairman of the United States House Committee on Expenditures in the Department of War during the Thirty-first and Thirty-second Congresses. He was not a candidate for renomination in 1852. He resumed the practice of law. He was an unsuccessful candidate for president judge of the twenty-second judicial district of Pennsylvania in 1853. He moved to Mauch Chunk, Pennsylvania in present-day Jim Thorpe, Pennsylvania, in 1853 where he continued the practice of law and also engaged in the banking business. He died there in 1872, and was buried in Mauch Chunk Cemetery.
