He was raised on a farm in Gallia County, Ohio, where he attended local public schools.

At that time, the California Gold Rush was underway and he spent the next two years mining and working in trade jobs.

In 1852, his family crossed the North American plains in an ox-drawn wagon to join Gates on the west coast.

In 1854, Gates and his family moved to the south side of the river to avoid an Indian uprising in their area.

[4][7] Once he was settled in the Fort Dalles area, Gates became involved in both Oregon territorial politics and local government affairs.

[9] On September 15, 1855, Gates was selected as chairman of a meeting of local residents held to discuss organizing a city government for the community around Fort Dalles.

It was decided that the community would hold an election to select trustees to oversee the town's development.

[10] Members of the community also selected Gates as their delegate in the territorial House of Representatives and directed him to introduce a bill to incorporate Dalles City.

At that time, Wasco County included all of eastern Oregon and southern Idaho from the crest of the Cascade Range to the summit of the Rocky Mountains, a total of about 130,000 square miles (340,000 km2).

[12][13][14] During the session, Gates introduced a bill to incorporate the Fort Dalles community, as instructed by his constituents.

No other candidates ran for the territorial representative position, since it was hoped that statehood would be achieved prior to the next regular legislative session.

By December, no statehood decision had been made, so the territorial legislature was seated to conduct required government business.

When the territorial legislature was convened on December 6, 1858, Gates served as chairman of the credential committee.

At the close of the session, Speaker Gates noted that the conflict regarding the capital's location divided the legislature but that the discussion on the issue was conducted with courtesy that reflected credit on the members of the House.

[20][23][26] When Oregon became a state, the territorial government ceased to exist, and Gates returned to Dalles City.

In 1859, he was elected to the Oregon Democratic Party's newly formed state central committee, representing Wasco County.

The convention nominated him as a presidential elector for Horace Greeley, who was running against Ulysses S. Grant that year.

[39] Governor Grover also promoted Gates to the rank of brigadier general in the Oregon militia.

As chairman, he was responsible for overseeing a $30,000 offering of state warrants to finance construction of the road.

[47][48] In 1880, Gates decided to run for the Oregon State Senate seat representing Wasco and Lake counties.

[50][51][52] Since state senators served a four-year term, Gates did not have to run for re-election prior to the 1882 legislative session.

Oregon's twelfth regular legislative session began on September 11, with Gates again representing Wasco and Lake counties.

[55] The most important decision the legislature had to make in 1882 was the election of a United States senator to represent Oregon.

The legislature eventually chose Republican Joseph N. Dolph to fill Oregon's open senate seat.

Gates's four-year state senate term expired at the end of 1883 without any additional legislative meetings.

[54] After the 1882 legislative session ended, Gates returned to his law practice and business interests in The Dalles.

Gates served on a committee promoting a project to build locks at the Columbia River cascades to allow steamships to navigate around the falls and continue upstream beyond the rapids.

[60] In 1886, Gates and two partners founded the Hood River and Miller Creek Water Ditch and Flume Company.

The company published a Wasco County newspaper, The Sun, which advocated for the Democratic Party and its candidates.