William Daniels talks playing Mr. Feeny, childhood abuse and Trump

At 89, William Daniels has had one of Hollywood’s longest and most-prolific careers, with roles that have spanned his more than 70 years in the limelight. The actor, who is instantly recognizable with his signature mustache, sat down with Fox News in a booth Los Angeles deli, with his wife of more than 65-years by his side, to discuss his headline-making new memoir "There I Go Again: How I Came to Be Mr. Feeny, John Adams, Dr. Craig, KITT, & Many Others."

Daniels is known to different generations for the types of roles that have staying power – though he may not have necessarily played the lead. In “Boy Meets World” he was the level-headed Mr. Feeny, on “St. Elsewhere,” the arrogant and at times angry Dr. Mark Craig. In “Knight Rider” he was the voice of KITT, and in “1776” he was John Adams.

He said his favorite role of them all was playing second President of the United States “simply because I played it on Broadway for two years.”

“It was a big part of my life,” he recalled over a mid-morning meal that included eggs, bacon and coffee. “After a while I began to enjoy it tremendously. When an actor gets a chance to work on a role, even when he is playing it, that is what I did and it always kind of remained fresh for me."

Daniels admits in his memoir that his foray into show business wasn’t his idea. His mother, he writes, dragged him and his sisters to endless auditions and had him learn to sing and dance so he could perform on cue, often rehearsing into the early hours of the morning.

"I wasn't aware of the abuse,” he told us. “I need an analyst to tell me I was an abused child. ‘What do you mean?’ she said. ‘You were abused, you were forced into this.' And then I realized I was nervous even though I didn't realize it at the time."

His career in Hollywood eventually led him to work alongside his wife Bonnie Bartlett, who played his fictional wife on “St. Elsewhere.”

As Daniels discusses his memories, Bartlett often chimes in.

But Daniels never planned to share his life story in a book.

"I just found myself picking up a pen and a yellow pad one day and start writing,” he described. “In retrospect I question my memory sometimes; it’s bad except for dialogue. As soon as you pick up a pen and start writing, it's like you open a door to your memory and that's the way it was with me. I was able to -- over months – [recapture] my youth, my whole experience in show business, with my sisters and [myself]."

In the memoir, the star discusses a role that has stuck to him firmly – the wise character of Mr. Feeny. Daniels began playing George Feeny in 1993 and most recently reprised the role this year in the spinoff “Girl Meets World.” But he nearly said no to playing Feeny in the first place, he revealed.

William Daniels as Mr. Feeny on 'Girl Meets World'

William Daniels as Mr. Feeny on 'Girl Meets World' (Disney)

"I went to the first rehearsal, and it was for a teacher and I didn't want to play a dumb or humorous, gaggy kind of thing. I always respected teachers," he said while picking at a bowl of cut-up fruit.

Daniels said he tried to get out of playing the part.

"I went to Michael Jacobs, the producer, and I said 'I quit,' and he said 'Bill, give me until tomorrow, and I'm going to rewrite the part.’ He rewrote the whole part in a very acceptable way for me."

As Daniels and his wife Bonnie Bartlett wrapped up their meal, they turned their attention to the current political climate in the U.S.

"These young people have to pay attention to say Mr. Trump,” Daniels advised. “In my mind, he is totally unsuitable for the presidency and could get us into grave trouble. I will keep my fingers crossed that I am wrong about that word.”

Bartlett, 87, said she feels young people need to be “to be good citizens” and Daniels said it’s imperative that they educate themselves about politics.

“They have to pay attention because I know they are busy just learning what they want to do and life and love and dating but they have to pay attention to the national situation and vote as soon as they can,” he said.

The star also had some advice for younger actors hoping getting their starts in show business now.

"Work hard, get a lot of rest and just keep at it because it is a very competitive business, and if you really have talent with perseverance you will make a life for yourself and if you don't have talent I suggest you get out of it."

"There I Go Again: How I Came to Be Mr. Feeny, John Adams, Dr. Craig, KITT, & Many Others" is in bookstores now.