In the House of Representatives he supported an interventionist foreign policy, anti-communism, Native American rights, and development in Wyoming.

In 1926, he attended the Junior Chamber of Commerce national convention in Jacksonville, Florida, to represent Indiana and parts of Ohio and Kentucky.

[14] During the campaign he praised President Herbert Hoover and was endorsed by the prohibitionist Anti-Saloon League in the primary and the anti-prohibitionist Association Against the Prohibition Amendment in the general election.

On December 19, Harrison announced that he would seek the Republican nomination for Wyoming's at-large congressional district and filed to run on May 31, 1950.

[26][27] During the primary he spent $1,752.42 and defeated Deputy Secretary of State T. C. Thompson and Homer Oxley for the Republican nomination on August 22.

[30][31][32] On May 7, 1952, Harrison announced that he would seek reelection to the House of Representatives in a letter to Ewing T. Kerr, the chairman of the Wyoming Republican Party, and filed to run on May 27.

[40] In the general election he defeated state representative Robert R. Rose Jr. with sixty percent of the popular vote after spending $2,385.14.

[47][48] On June 10, Harrison announced that he would run in the Senate election and Morton Spence dropped out of the Republican primary and endorsed him.

[64] After leaving the Housing and Home Finance Agency, Harrison worked for the farm division of the Republican National Committee in Chicago, Illinois.

[67][68] Harrison later resigned from his position as congressional liaison for the Housing and Home Finance Agency so that he could lead the Barrett-for-Senator Committee in Sheridan County during the 1958 election.

[69] On September 10, 1959, Harrison announced at the Wyoming State Bar Association convention that he would run for the Republican nomination in either the Senate or House election.

[71] On May 24, 1960, Harrison filed to run in the Republican primary and narrowly defeated Kenneth L. Sailors, Mark Cox, Walter Kingham, and R. L. Greene after spending $8,897.

[79][80] During the general election, Harrison was forced to suspend campaign activity to attend a top security meeting, open to only members of Congress and governors, regarding the Cuban Missile Crisis.

[84][85] In the general election, he was narrowly defeated by Teno Roncalio, who benefited from the coattail effect of President Lyndon B. Johnson's victory in Wyoming against Republican presidential nominee Barry Goldwater.

[107] During the 1932 House election, Harrison gave support to maintaining and repealing the 18th Amendment which banned the production, transport, and sale of intoxicating liquors.

[16][17] In 1961, Harrison sent telegrams to Speaker Sam Rayburn and President pro tempore Carl Hayden asking them to work for the passage of an amendment giving residents of Washington, D.C., the ability to vote in presidential elections.

[113] On September 5, 1961, Harrison introduced legislation to prohibit the receipt, handling, and transportation of mail determined to be communist propaganda by the attorney general.

[117] In May 1953, Harrison wrote a letter to President Dwight D. Eisenhower and Secretary of the Interior Douglas McKay asking for Fort Phil Kearny to be registered as a national historic landmark.

[119] On July 14, 1953, he introduced legislation to abolish the Shoshone Cavern National Monument and offer the land to Cody, Wyoming, for use as a public park.

[124][125] Harrison and Senators Joseph C. O'Mahoney and Lester C. Hunt wrote to Rawlins, Wyoming,'s Chamber of commerce giving support to plans to create a wool processing mill.

[130] On November 21, 1950, Harrison met with representatives of the Arapaho and Eastern Shoshone tribal business councils, who were seeking help in extending a bill giving semi-annual payments from the federal government, which was set to expire in March 1952.

[131] In September 1951 and January 1953, he introduced legislation to increase the per capita payments to the Arapaho and Shoshone tribes living in the Wind River Indian Reservation.

[132][133] In 1953, Harrison introduced House concurrent resolution 108, which would release all Native Americans from the administration of the Bureau of Indian Affairs.

[136] On May 9, 1968, Harrison introduced a resolution asking for President Lyndon Johnson to declare June 30, as that would have been the 100th anniversary of the Wind River Indian Reservation, as National Original Americans Day.

[110] He supported General Douglas MacArthur's letter to the Veterans of Foreign Wars national convention in which he stated that the island of Taiwan should be defended at any cost due to its strategic importance as an "unsinkable aircraft carrier and submarine tender".

[144] Harrison disagreed with the British criticism of the United States' bombing of the Sui-ho Dam on the Yalu River, as he felt that it was necessary to bring a successful and quick end to the war.

[147] On February 15, 1951, he was one of over one hundred Republican members of Congress that signed a declaration demanding Congressional participation in foreign policy.

[148] Harrison supported the release of William N. Oatis, a journalist who was charged with espionage by the Czechoslovak Socialist Republic and sentenced to ten years in prison.

[152] However, Harrison was absent when the House of Representatives voted 189 to 158 in favor of giving the final decision on the wheat exports to President Lyndon B. Johnson on December 24.

[153] In 1966, Harrison gave support to bombing the North Vietnamese port of Haiphong while debating Mayne Miller at the University of Wyoming.