He's from Sylvan Hills, a neighborhood in Atlanta, and grew up in the notorious Jonesboro South projects in the city's Zone 3. Other rappers from the neighborhood include Waka Flocka Flame, 2 Chainz, Ludacris, and Thug's childhood friend PeeWee Longway, from whom he lived four doors down.

Young Thug was born Jeffery Lamar Williams in Atlanta, the tenth of eleven children, on August 16, 1991.

He has told interviewers that he was expelled in the sixth grade for breaking a teacher's arm and was sent to juvenile prison for four years.

Thug initially released a series of independent mixtapes beginning in 2011 with I Came from Nothing, followed by I Came from Nothing 2 (also 2011) and I Came from Nothing 3 (2012). In 2013, he signed with Gucci Mane's 1017 Records, and later that year he released his label debut mixtape 1017 Thug to critical praise.

"I can't remember 16 bars," he noted in a 2015 interview. "I just do it bar for bar. I did a song in eight minutes. I thought everybody could write songs that fast. But working with a lot of them, they don't. Wayne and Drake, it takes them so long to do a song. I understand why, because they want it to be perfect. But I think I can do a perfect song in ten minutes. I did 'Danny Glover' in eight minutes. 'Stoner' took me almost an hour."

"Run that money up, like ya 'bout to start trial
When you beat the case, turn into a stoner child
We don't stand in line, foreign shoes hurt your feet
Everybody stoned, weed, lean, molly, E"

In 2017, Thug featured on the hit song "Havana" by Cuban pop singer Camila Cabello. The song was a global megahit, reaching number one in twenty-three countries worldwide.

So Much Fun (2019) debuted at number one on the US Billboard 200 and included the Billboard Hot 100 top-twenty singles "The London" and "Hot".

The December 4, 2014 issue of Rolling Stone called Young Thug the "most exciting new voice of hip-hop" and "hip-hop's new crown prince." According to The Fader, "in a typical Young Thug verse, he slurs, shouts, whines and sings, feverishly contorting his voice into a series of odd timbres like a beautifully played but broken wind instrument." Billboard wrote that "Thug uses this multiplicative vocal delivery to his advantage: where another rapper might lapse into repetition, he finds a new way to distress and warp his tone, to burrow resourcefully into rhythmic cracks and crevices." Thug himself has said, "I'm in the studio so much, I'll just try stuff. I just think and try, think and try. I don't really know how to sing, but I've been trying for years."

The song spawned a number of unofficial remixes by several rappers, including Wale, Jim Jones, Jadakiss, Iamsu! and Trick-Trick, among others. Thug expressed his disapproval for the remixes, commenting "If you feel like my song isn't tough enough to the point where you have to freestyle... Don't think I'm happy that you're doing it because of who you are. I'm ready for war."