Fitch kept up his law studies and in 1864 was admitted to the bar by the Nevada Supreme Court.
In the same year he was elected from Virginia City as a delegate to the Nevada State Constitutional Convention.
He was nominated by the Union Party and unsuccessfully campaigned for the role as territorial delegate to Congress from the Nevada Territory in 1864.
He also campaigned across Nevada for Abraham Lincoln and Andrew Johnson.
In 1865 Fitch moved to Washoe County and soon after was appointed county district attorney.
When his term as district attorney expired in 1866, he moved to Belmont, Nevada, and practiced law there until 1868.
He was elected as a Republican to the U.S. House of Representatives and the Forty-first Congress of the United States, serving from March 4, 1869 – March 3, 1871, and opened his first law practice.

In December 1869, he spoke against the pending anti-polygamy Cullom Bill, which would strip the Utah territory's residents of local authority.
It proposed instead to outlaw the Utah  Territorial Legislature, eliminate the offices of the territorial marshal and attorney general and transfer their authority to federal officers, give the federally appointed Governor the authority to appoint all officers in the territory, excluding constables, and place all local and territorial matters in the hands of federally appointed officials.
Fitch attempted to persuade Congress that they should avoid the prospect of another Mormon war.

His opposition to the bill may have cost him votes at home, and he was not reelected in 1870 even though he represented the dominant Republican party.
In 1870, his wife published her first novel, Bound Down: Or Life And Its Possibilities.
Tom and his wife published Better days: or, A millionaire of to-morrow in 1891, and she wrote two more books in 1891 and 1893.
Fitch kept up his law studies and in 1864 was admitted to the bar by the Nevada Supreme Court. In the same year he was elected from Virginia City as a delegate to the Nevada State Constitutional Convention. He was nominated by the Union Party and unsuccessfully campaigned for the role as territorial delegate to Congress from the Nevada Territory in 1864. He also campaigned across Nevada for Abraham Lincoln and Andrew Johnson. In 1865 Fitch moved to Washoe County and soon after was appointed county district attorney. When his term as district attorney expired in 1866, he moved to Belmont, Nevada, and practiced law there until 1868. He was elected as a Republican to the U.S. House of Representatives and the Forty-first Congress of the United States, serving from March 4, 1869 – March 3, 1871, and opened his first law practice.
In December 1869, he spoke against the pending anti-polygamy Cullom Bill, which would strip the Utah territory's residents of local authority. It proposed instead to outlaw the Utah  Territorial Legislature, eliminate the offices of the territorial marshal and attorney general and transfer their authority to federal officers, give the federally appointed Governor the authority to appoint all officers in the territory, excluding constables, and place all local and territorial matters in the hands of federally appointed officials. Fitch attempted to persuade Congress that they should avoid the prospect of another Mormon war.
His opposition to the bill may have cost him votes at home, and he was not reelected in 1870 even though he represented the dominant Republican party. In 1870, his wife published her first novel, Bound Down: Or Life And Its Possibilities. Tom and his wife published Better days: or, A millionaire of to-morrow in 1891, and she wrote two more books in 1891 and 1893.
Thomas Fitch (politician)