"Na-Nu Na-Nu." With that silly, unintelligible catchphrase, Robin Williams found a place in the heart of TV fans across the globe and became a permanent fixture in Hollywood in 1978 through the popular TV shows "Happy Days" and "Mork & Mindy." He would later go on to portray a cartoon genie in "Aladdin," a father in drag in "Mrs. Doubtfire" and a complex role model in "Good Will Hunting," for which he won his lone Academy Award. Williams, 63, died in an apparent suicide due to asphyxia Monday after battling severe depression. His death came as a shock to many fans after a decades-long career that examined the highs and lows of the human condition, with laughter often seeming to triumph over all in the end. 

"You look at the world and see how scary it can be sometimes and still try to deal with the fear," he told the Associated Press in 1989. "Comedy can deal with the fear and still not paralyze you or tell you that it's going away. You say, OK, you got certain choices here, you can laugh at them and then once you've laughed at them and you have expunged the demon, now you can deal with them. That's what I do when I do my act."

From his breakout role as the alien in "Mork & Mindy," through his memorable film characters, the Juilliard-trained Williams brought emotion and life to every role with his manic monologues and elaborate mannerisms. Williams won three Golden Globes, for "Good Morning, Vietnam," "Mrs. Doubtfire" and "The Fisher King," the Associated Press said. He also gave noteworthy performances in "Hook," "The Birdcage" and "Jumanji."

"In one two-year period I made eight movies," he told The Guardian in 2010. "At one point, the joke was that there's a movie out without you in it. You have this idea that you'd better keep working otherwise people will forget. And that was dangerous. And then you realize, no, actually if you take a break people might be more interested in you."

Williams' personal battles were never a secret. He kicked a cocaine habit in the early 1980s, right around the time of the birth of his oldest child, Zak Williams, the comedian’s son by his first wife, Valerie Velardi, according to the New York Times. But it was not an easy addiction to overcome. 

“There was still, in the background, this voice, like, ‘Psst,’” Williams told the New York Times in 2009, “So when I relapsed, I went back hard. The one thing I hadn’t dealt with was, how honest do you want to live?”

Friends said Williams was deeply sensitive. “He’s an easy cry, whether he wants people to know that or not,” actor Billy Crystal, Williams' friend since the late 1970s, told the New York Times in 2009.