Langer was born on September 30, 1886 near Casselton, Dakota Territory, to Frank and Mary (Weber) Langer. His father, Frank Langer, was a member of the first legislature of the state of North Dakota. William was valedictorian of Casselton High School upon graduation in 1904. He obtained a bachelor of laws from the University of North Dakota in Grand Forks, but was too young upon graduation to practice law. He therefore continued his undergraduate education at Columbia, where he graduated at the top of his class in 1910. Although he was offered a position at a prominent New York law firm, he elected to return to North Dakota, where he practiced law in the town of Mandan before starting his career in politics. He married Lydia Cady, the daughter of New York architect J. Cleaveland Cady, in 1918, and had four daughters, Emma, Lydia, Mary, and Cornelia (who became a wife of abstract impressionist painter Kenneth Noland).
In 1914, Langer was appointed state's attorney of Morton County and was one of a few non-farmers on the Nonpartisan League Republican 1916 state ticket. He was elected state attorney general as the newly formed NPL party swept to victory in the 1916 election, but soon clashed with the party's founder and mercurial leader Arthur C. Townley. By 1920, Langer was publicly accusing Townley of Bolshevism, and failed in a primary campaign to replace the incumbent NPL governor Lynn Frazier as the party's gubernatorial candidate. Langer's break with the NPL leadership was a reflection of the infighting that limited the party's eventual influence on North Dakota politics.
Langer eventually mended his rift with the NPL and was elected governor of North Dakota in 1932. As governor, Langer in 1933 required all state employees to donate part of their annual salaries to the NPL and to the Leader, a weekly newspaper owned by high-ranking officials in his administration. Collecting this money was not prohibited by state law and was a common, traditional practice. However, when donations were made by highway department employees, who were paid through federal relief programs, the US Attorney, P. W. Lanier charged that the donations constituted a conspiracy to defraud the federal government. Brought to trial in 1934, Langer and five co-conspirators were found guilty. The trial was presided over by Judge Andrew Miller and was prosecuted by U. S. District Attorney for North Dakota P. W. Lanier, two of Langer's strongest political opponents in the state.
The first trial was littered with procedural errors which made it invalid on appeal, including improper and rigged jury selection (the jurors were alleged to have had personal bias against Langer and hand-picked by the prosecutor) and heavily biased and opinionated jury instructions.
Because of the felony conviction, the North Dakota Supreme Court ordered him removed from office, and on July 17, 1934, the Court declared Lieutenant Governor Ole H. Olson the legitimate governor. Langer gathered with about ten friends, declared North Dakota independent, declared martial law, and barricaded himself in the governor's mansion until the Supreme Court would meet with him. Langer eventually relented, and Olson served the remainder of Langer's term as governor.
In 1935 the convictions were overturned on appeal. The case against Langer was retried twice in 1935. Judge Miller, following a recusal motion by Langer, refused to step down as judge in the first retrial, which resulted in a hung jury. In between the second and third trials, U.S. Attorney Lanier filed charges against Langer for committing perjury in his recusal motion against Judge Miller. This trial, unprecedented in its nature on perjury in an affidavit requesting a recusal, resulted in a directed verdict to acquit Langer. The second retrial of the original charges, finally presided over by a judge other than Miller resulted in Langer's acquittal.
Throughout all of the trials, Langer maintained that he was innocent and was the victim of a political vendetta from Judge Miller and U.S. Attorney Lanier, and was returned to the governorship in the 1936 election. Historian Lawrence Larsen calls him "a master of "political theater."
Langer's wife, Lydia, ran for governor in 1934 but lost.
In 1938 Langer ran for the Senate as an independent, and received 42% of the vote; he was defeated by Republican Gerald Nye.
The 1940 election was another very dramatic one. Langer defeated incumbent Lynn Frazier in the Republican primary, and then faced both the Democratic candidate, Charles Vogel, and Republican/NPL Congressman William Lemke, who declined to run for reelection to Congress in order to run for the Senate as an independent. Langer won the election with 38% of the vote.
Because of the trials mentioned above, Langer's qualifications were questioned under Article 1, Section 5 of the Constitution, which declares the U.S. Senate to be the ultimate judge of the elections, qualifications, and returns of its members. The Senate seated Langer conditionally and then began an investigation into his trials. The Committee on Privileges and Elections found Langer guilty of "moral turpitude" and was judged unqualified to be a U.S. senator. The full Senate reversed the committee, and voted to seat Langer.
Senator Langer was an isolationist, wanting to minimize America’s involvement in World War II. At home, he concentrated on making life easier for the farmers of North Dakota by raising wheat prices and granting government relief, although amidst rumors of great scandal. He was also very adamant about implementing affordable healthcare for everyone. As a senator, he served on the Post Office, Civil Service and Indian Affairs committees. He and Henrik Shipstead of Minnesota were the only senators to vote against the United Nations Charter in 1945. He was also one of the seven senators who opposed full United States entry into the United Nations.
He proposed a bill for the United States federal government to pay for the repatriation of African-Americans to the African continent, after being asked to do so by African-American organizations. The bill, called S. 1800, failed to pass.
In September 1950, Langer filibustered to prevent the override of President Truman's veto of the McCarran Internal Security Act, for five hours, before collapsing.
Following the merger of the Nonpartisan League with the state Democratic party, Langer remained on the Republican ticket in the 1958 Senate elections, and won without making a single campaign appearance in the state. Langer died in Washington, D.C. on November 8, 1959.1914–1916: State's Attorney for Morton County
1916–1920: Attorney General of North Dakota
1933–1934: Governor of North Dakota (removed from office)
1937–1939: Governor of North Dakota
1941–1959: United States Senate
"The Famine in Germany", Published by U.S. Govt. print. off., 1946