The 33-year-old Grammy-winning artist, whose given name is Jeffery Williams, entered his pleas without reaching a deal with prosecutors after negotiations between the two sides broke down, lead prosecutor Adriane Love said.
That left the sentence in Atlanta, Georgia completely up to Fulton County Superior Court Judge Paige Reese Whitaker.
The judge imposed a sentence of 40 years, with the first five to be served in prison but commuted to time served, followed by 15 years on probation.
If the music artist successfully completes that probation without any violations, another 20 years will be commuted to time served.
But if he violates the conditions, he will have to serve those 20 years.
Young Thug must stay away from the metro Atlanta area for the first 10 years of his probation, except for weddings, funerals, graduations or serious illness of family members, the judge said.
But she also ordered him to return to the Atlanta area four times a year during his probation to make a live anti-gang, anti-gun violence presentation at a school or a community organisation serving children.
She said that can count toward the 100 hours of community service she ordered him to perform each year during probation.
He's also not allowed to associate with gang members or with the victims or other defendants in the case, with the exception of his brother and the rapper Gunna, with whom he has contractual obligations.
He also cannot promote any criminal street gang or gang activity and can't use hand signs or terminology that promotes a street gang.
Additional conditions include submitting to random drug screens and not possessing a gun. But he is allowed to travel both nationally and internationally for work, even while on probation.
Young Thug pleaded guilty to one gang charge, three drug charges and two gun charges.
He also entered a no-contest plea to another gang charge and a racketeering conspiracy charge, meaning he decided not to contest those charges but can be punished for them as if he had pleaded guilty.
Young Thug asked the judge to let him go home, saying he wouldn't be in a similar situation again.
"I've learned from my mistakes. I come from nothing and I've made something and I didn't take full advantage of it. I'm sorry," he said.
The judge said she appreciated that he realised the impact he has on people worldwide.
She said rap music may involve a lot of posturing but children emulate some of the dangerous behaviour mentioned in songs.
She encouraged Young Thug to use his talent and influence to encourage kids to do the right thing.
"I want you to try to be more of the solution and less of the problem," Whitaker said.
A tremendously successful rapper, Young Thug started his own record label, Young Stoner Life or YSL. Prosecutors have said he also co-founded a violent criminal street gang and that YSL stands for Young Slime Life.
