In 1935, Halleck was elected to fill the House vacancy created by the death of Congressman-elect Frederick Landis, and remained in that position until 1969.

He rejected the Democratic "don't-change-horses-while-crossing-the-stream" mantra and declared that a Republican president would retain George C. Marshall, Dwight Eisenhower, Douglas MacArthur, and William F. Halsey in their military positions.

He attacked what he called the New Deal "snooping into our ice boxes," a reference to the Office of Price Administration and rationing.

[16] Along with Senator Everett Dirksen, he was the face of the Republican Party in most of the 1960s, and both made frequent appearances on television news and talk programs.

After the heavy election setbacks of 1964, Halleck was defeated in his bid to remain Minority Leader by Gerald Ford, who was the nominee of the Young Turks.

[21] His son, Charles W. Halleck, became an attorney in Washington, D.C., and was a judge of the Superior Court of the District of Columbia.