Born in Champaign County, Illinois, he moved to Kansas with his family when he was four years old. After completing a basic education, he taught school for a single year then began work as a federal employee, a position he would serve in different capacities for the next thirty years. He first worked for the railroad mail carrier service, rising to be superintendent of several areas throughout the Midwest and then to the Railway Adjustment Division, Post Office Department superintendent. He resigned to run his Parsons, Kansas newspaper, the Parsons Sun. He then became Governor Henry J. Allen's personal secretary.

He was elected Governor of Kansas in 1929, known as a candidate for being extremely progressive. Shortly after he moved into the governor's mansion, the Great Depression began. Reed called an extra session of the state legislature to combat the troubles faced by Kansans dealing with the depression. The governor decided not to run for re-election, and returned to newspaper editing. When the anti-Semitic preacher Gerald B. Winrod ran for the Republican nomination for the United States Senate in 1938 and seemed likely to win it, Reed was recruited by the mainstream political establishment as a popular figure who could prevent Winrod's election. Reed won the nomination and the election, and was re-elected in 1944. While in the Senate, his fellow Kansas Senator was also a former governor, Arthur Capper. He attempted to obtain the 1942 Republican nomination for governor of Kansas but failed.

Reed died in 1949 while on a visit home from the Senate. The papers from his Senate years are said to have been destroyed. He was buried in Oakwood Cemetery in Parsons.