Robert Downey Jr.'s Oscar triumph has many cheering for the actor after years of drug addiction that began during his troubled childhood.

The Iron Man actor won his first Academy Award for his role as Lewis Strauss in Oppenheimer. 

In his acceptance speech, he said, "I’d like to thank my terrible childhood and the Academy — in that order."

Downey Jr.'s troubled childhood

Downey Jr. had a chaotic, restless childhood surrounded by drugs.

His father, counterculture filmmaker Robert Downey Sr., shunned steady employment to make bizarre, often disturbing, low-budget movies. The family was frequently on the move, and Downey Jr.'s first acting roles were in his father's trippy, surreal films, like Pound and Greaser's Palace. 

The content of the movies was hardly kid friendly. Pound was about dogs waiting to be euthanized; Downey Jr.'s only line in the movie refers to male genitalia.

At age six, Downey Jr. was introduced to drugs by his father, who later said he regretted the decision.

"I passed him a joint. And suddenly I knew I had made a terrible, stupid mistake… Giving a little kid a toke of grass just to be funny," he told Vanity Fair. 

Amazing comeback

Downey Jr.'s childhood took another traumatic turn when his parents divorced at age 12. He dropped out of high school to pursue acting.

When his Hollywood career started taking off in the 1990s, Downey Jr. entered a highly publicized, years-long spiral, spending time in and out of rehab and jail. During one of his erratic, drug-fueled episodes, he wandered into a neighbor's home and fell asleep in a child's bed.

He once told a judge that doing drugs was "like I have a shotgun in my mouth, and I've got my finger on the trigger, and I like the taste of the gun metal."

Downey Jr. finally got sober in 2003, and he went on to experience a career resurgence as Marvel's Iron Man, eventually becoming the highest-paid actor in the world at one time. He expanded his repertoire with a dramatic role in Christopher Nolan's Oppenheimer, which won the Oscar for Best Picture.

The actor credited his wife Susan with bringing him back from the brink.

“She found me, a snarling rescue pet, and loved me back to life. That’s why I am here,” he said.