He was elected to the United States House of Representatives in 1902 from the Sixth District of Arkansas, and was re-elected to four subsequent terms, serving until 1913.

Senator Jefferson Davis had died on January 3, after the legislature had re-elected him to a new term beginning March 4, 1913; his seat was now open.

He championed the Keating-Owen Child Labor Act and worked to enact bills to regulate railroads and other key industries.

Senior Democratic Senator Furnifold Simmons was expected to take Underwood's place, but withdrew his name from consideration after Robinson challenged him for the position.

A Capitol Hill resident, he never strayed far from the Senate chamber, but kept a constant watch over the proceedings in order to capitalize on any dissension within the Republican ranks.

Known as a "horse trader," he made deals on both sides of the aisle and helped facilitate negotiations with the era's GOP presidents.

At the Chevy Chase Country Club (a favorite haunt for Washington politicians), a fellow golfer asked to move ahead of the senator's slow-playing foursome.

[8] As Franklin Roosevelt's New Deal "marshal," he ensured the passage of countless bills relating to the Depression and social policy, his most impressive victory being the Emergency Banking Act, which he pushed through both houses of Congress in seven hours.

[11] Richard L. Riedel, a Senate press gallery attendant in the 1920s and 1930s, recalled, "When [Robinson] would go into one of his rages, it took little imagination to see fire and smoke rolling out of his mouth like some fierce dragon.

Robinson could make Senators and everyone in his presence quake by the burning fire of his eyes, the baring of his teeth as he ground out the words, and the clenching of his mighty fists as he beat on the desk before him.

"[12] The press referred to him as "scrappy Joe", and he nearly fought with Senate colleagues Robert M. La Follette, Porter J. McCumber, James Thomas Heflin, and Huey Long.

Early in 1928, Robinson clashed with Senator James Thomas Heflin, a Democrat from Alabama, who frequently inserted anti-Catholic sentiments into many of his speeches.

Robinson admonished Heflin's views, stating that religious affiliation had no bearing on a person's credentials for higher office.

On one famous occasion, he declared, "I have heard [the senator] denounce the Catholic Church and the Pope of Rome and the cardinal and the bishop and the priest and the nun until I am sick and tired of it, as a Democrat."

Helfin retorted, "The Senator from Arkansas can not remain leader of the Democrats and fight the Roman Catholics' battle every time the issue is raised in this body."

He continued to score victories as the Senate's minority leader, but his cooperative relationship with Hoover riled the members of his party.

The Senate chaplain gave a brief sermon, and the United States Capitol Police escorted his body to a funeral train headed to Little Rock.

Thousands of mourners traveled to the Arkansas capitol to witness Robinson's lying-in-state ceremony and to express their grief and their enormous admiration for the majority leader: the "fightingest" man in the U.S.

In an aside that illustrates the complexities of Southern political allegiances during the relevant period, Portis's narrator Mattie Ross says: "[Grover Cleveland] brought a good deal of misery to the land in the Panic of ’93 but I am not ashamed to own that my family supported him and has stayed with the Democrats right on through, up to and including Governor Alfred Smith, and not only because of Joe Robinson."