He held the position of solicitor general in the Justice Department from 1913 to 1918, during which time he successfully argued for the unconstitutionality of the grandfather clause in Oklahoma's constitution, which had a discriminatory effect against African-American voters, in Guinn v. United States.

After he left office, Davis helped establish the Council on Foreign Relations and advocated for the repeal of Prohibition.

He continued as a prominent attorney, associated with several law firms over the years, and represented many of the largest companies in the United States from the 1920s onwards.

In addition to his legal work, Davis was also involved in the New York City Bar Association, serving as its president from 1931 to 1933.

During the last two decades of his career, Davis represented large corporations before the Supreme Court, challenging the constitutionality and application of New Deal legislation.

He lost many of these cases but scored a major victory in Youngstown Sheet & Tube Co. v. Sawyer (1952), in which the Supreme Court ruled against President Harry Truman's seizure of the nation's steel plants.

Davis unsuccessfully defended the "separate but equal" doctrine in Briggs v. Elliott (1952), one of the companion cases to Brown v. Board of Education (1954), in which the Court ruled that segregated public schools were unconstitutional.

Catherine was the daughter of Tobias Martin, dairy farmer and amateur poet, and his wife, a member of the Esdale family.

In all times and all countries has he stood forth in defense of his nation, her laws and liberties, not, it may be, under a shower of leaden death, but often with the frown of a revengeful and angry tyrant bent upon him.

Before Davis had completed his first year of private practice, he was recruited to Washington & Lee Law School as an assistant professor, starting in the fall of 1896.

Davis acquired much of his father's southern Democratic politics, opposing women's suffrage, Federal child-labor laws and anti-lynching legislation, and Harry S. Truman's civil rights program.

Davis ranked as one of the last Jeffersonians, as he supported states' rights and opposed a strong executive (he would be the lead attorney against Truman's nationalization of the steel industry).

As Solicitor General, he successfully argued in Guinn v. United States for the unconstitutionality of the grandfather clause in Oklahoma's constitution.

Davis proselytized in London for the League of Nations based on his paternalistic belief that peace depended primarily on Anglo-American friendship and leadership.

Although Tennessee's Andrew Johnson served as president after Lincoln was assassinated, Davis's nomination made him the first presidential candidate from a former slave state since the Civil War, and as of 2024 he remains the only ever nominee from West Virginia.

Davis admitted he was an organization man, looking a bit annoyed by the way he was being put through his paces, and then turned quickly to Mike Hennessy of the Boston Globe and engaged him in conversation.

Davis was a member of the National Advisory Council of the Crusaders, an influential organization that promoted the repeal of Prohibition.

He was the founding president of the Council on Foreign Relations, formed in 1921, chairman of the Carnegie Endowment for International Peace, and a trustee of the Rockefeller Foundation from 1922 to 1939.

[19] Davis was implicated by retired Marine Corps Major General Smedley Butler in the Business Plot, an alleged political conspiracy in 1933 to overthrow Roosevelt, in testimony before the McCormack-Dickstein Committee, whose deliberations began on November 20, 1934, and culminated in the Committee's report to the U.S. House of Representatives on February 15, 1935.

In 1933, Davis served as legal counsel for the financier J.P. Morgan, Jr. and his companies during the Senate investigation into private banking and the causes of the recent Great Depression.

[24][25][26] The last twenty years of Davis's practice included representing large corporations before the Supreme Court challenging the constitutionality and application of New Deal legislation.

While Davis wasn't brought into the case until March 1952, he was already familiar with the concept of a presidential seizure of a steel mill.

In 1949, the Republic Steel Company, fearful of advice given to Truman by Attorney General Tom C. Clark, asked Davis for an opinion letter on whether the President could seize private industry in a "National Emergency."

He further went on to opine on the Selective Service Act of 1948's intent, and that seizures were only authorized if a company did not sufficiently prioritize government production in a time of crisis.

Washington Post writer Chalmers Roberts subsequently wrote that rarely "has a courtroom sat in such silent admiration for a lawyer at the bar" in reference to Davis's oral argument.

[30] Of particular note in this case is that one of the justices in the majority was Tom Clark, who as attorney general in 1949 had advised Truman to proceed with the seizure of Republic Steel.

[31] Davis's legal career is most remembered for his final appearance before the Supreme Court, in which he unsuccessfully defended the "separate but equal" doctrine in Briggs v. Elliott, a companion case to Brown v. Board of Education.

Davis, as a defender of racial segregation and state control of education, uncharacteristically displayed his emotions in arguing that South Carolina had shown good faith in attempting to eliminate any inequality between black and white schools and should be allowed to continue to do so without judicial intervention.

He expected to win, most likely through a divided Supreme Court, even after the matter was re-argued after the death of Chief Justice Fred M. Vinson.

After the Supreme Court unanimously ruled against his client's position, he returned the $25,000 (equivalent to $300,000 in 2023),[32] that he had received from South Carolina, although he was not required to do so, but kept a silver tea service that had been presented to him.