He would become famous in 1950 for claiming that he suspected there were over 50 Soviet/ Communist sympathizers in the FDR and Truman White House. Considering that liberals had control of much of the country, and the minds of millions of Americans, he was laughed at and scorned to an early death.
The media still talks about McCarthy in a negative way, even though he has essentially been vindicated. Unfortunately, he would not be vindicated for another 41 years, or until the Soviet Union fell. Once this happened, the U.S. released secret documents it didn't want to release during the Cold War for fear of hurting any efforts of winning the Cold War. These secret documents were the Vinova Accords.
In 1991, after the fall of the Soviet Union, the U.S. released secret documents it didn't want to release during the Cold War for fear of hurting any efforts of winning the Cold War. These secret documents were the Venona Files.
The Venona Files showed (proved) that not only was McCarthy right about there being 50 soviet spies working for the FDR/ Truman administrations, there was over 300 spies.
Still, you don't hear much about this outside the conservative sphere. You will never learn this in the liberal public school systems. You will never learn about this by the liberal media. For this reason, many people still view McCarthy as a bad man who falsely accused people of being Communists. When, in truth, the evidence, if we so choose to check it out, shows that McCarthy was right.
In effect, we should consider McCarthy a hero rather than a villain. He would go on to serve as a Senator until 1957, until he died an untimely death. Some say he was ridiculed so much that he was driven to alcoholism, and died of hepatitis.