The author of one of the most successful anti-bully smackdowns of all time began his life as an Iowa farm boy, the son of English immigrants. He quickly fell in love with the law, frequently visiting the courthouse to watch trials.
Remember, this is before TV, and presumably fun, was invented.
Welch sold maps door-to-door to earn his college tuition, graduated Phi Beta Kappa from Grinnell College in 1914 and got a scholarship to Harvard Law School.
And yes, that is as difficult and impressive as it sounds.
Welch graduated from Harvard in 1917 with his law degree, but wasn't able to put it into use yet, as there was a whole war thing happening. He served as a Second Lieutenant in the Army until the end of World War I.
In 1919, Welch was admitted into the Massachusetts bar, and he settled in Boston. This is why he's generally described as a "Boston lawyer." It wasn't his birthplace, but rather his adopted hometown. He went to work for the law firm Hale and Dorr, where he spent his entire career as a respected attorney.
When McCarthy went on the warpath, Secretary Stevens of the Army tapped Welch as his counsel—unpaid, too. (Maybe Welch had a bit too much decency for his own good.) In any case, he already had an excellent reputation as counsel, and you know the Army wasn't going to take a chance on an unknown kid.
Welch seemed as cool as a cucumber during the hearings (although he later admitted otherwise), baiting McCarthy and his allies into losing their tempers. It was in one of these exchanges that McCarthy went too far, and provoked the "have you no sense of decency" response. This heartfelt question absolutely destroyed McCarthy.
After the hearings, Welch returned to his normal life. His first wife died in 1956, and he remarried a family friend in the following year. In 1959, he appeared in the Otto Preminger movie Anatomy of a Murder as a judge, nabbing a Golden Globe nom for his work. Not too shabby for a first-timer. (He said it was the only way he'd ever get to be a judge.) He died the next year, a few weeks shy of his 70th birthday.
Welch talked at length to colleagues after the hearings, confiding that he wasn't the cool customer he may have appeared on the small screen:
"There were many times when I sat stunned and speechless, and [the public] said, 'What patience the man has.' When I sat in an agony of indecision, [the public] said, 'How wise he is. . .' Sometimes I was so weary my mind was almost blank, and then some of [the public] would say, 'How witty he is!'" (Source)
Still, Welch is forever remembered for his takedown of McCarthy, meeting the senator's reckless anger and cruelty with a simple, human response. He showed that sometimes the best way to defeat a bully isn't to punch back, but to question why the bully is punching in the first place.