After the public school visit Jewell went with his father apprenticed to learn the tanning trade. Later he moved into the Telegrafiebranche; Akron (Ohio ), he was head of a telegraph office. From his marriage with Esther Dickinson had two children.
Jewell was one of the first members of the newly formed Republican Party in Connecticut. In 1867 he ran unsuccessfully for the Senate from Connecticut; in the following year, when he first ran for the office of governor of this state, Jewell suffered a defeat. In 1869, he sat down then against the Democratic incumbent James English.
After a year in office, he lost the next election, however, again against his predecessor. The change to the post of governor continued in 1871, when English although won the election, a committee of inquiry, however, revealed manipulations and the victory Jewell zusprach. This then also won the 1872 election, before he did not run after a total of three terms.
1873 took over Marshall Jewell then a completely different task, when U.S. President Ulysses S. Grant appointed him U.S. ambassador to Russia. After only seven months, he left St. Petersburg, however, again. At home, President Grant appointed him to the office of the Postmaster General ( Postmaster General ). The Cabinet, he belonged to until 1876.
In his party Marshall Jewell was one of the leaders. He was originally a 1876 contender to succeed the outgoing President Grant. Ultimately, he ran for the Republican National Convention as a vice presidential candidate behind Rutherford B. Hayes; with 86 votes but he landed behind William Almon Wheeler ( 366) and Frederick T. Frelinghuysen (89 ) only in third place. Hayes and Wheeler won the next election and made it to the White House.
However, Jewell was an important man among the Republicans. From 1880 until his death in 1883, he stood before the Republican National Committee.