But he’s never used his disability as a crutch, a reason to not live his life to the fullest. His attitude, he said, is due in large part to his mother, Antoinette Tuff, the DeKalb County school bookkeeper who was thrust into the spotlight in 2013 when she talked down an armed campus intruder.

That’s why her portrayal of him in a memoir, “Prepared for a Purpose: The Inspiring True Story of How One Woman Saved an Atlanta School Under Siege,” took him by surprise.

When he learned recently that her story was the subject of a new Lifetime movie, a project of Bishop T.D. Jakes and starring Toni Braxton, it was like adding insult to injury.

“She was all about people not treating me sympathetically,” he said. “She didn’t view me as disabled, she viewed me as normal.”

But in the book, Tuff said, his mother made it seem like he was incapable of taking care of himself.

“I’ve never sat back and let people do things for me,” he said in an email sent earlier this month.

Antionette Tuff, you might recall, was at work in the front office of the McNair Discovery Learning Academy on Aug. 20, 2013, when 20-year-old Michael Brandon Hill entered the school with a rifle and several hundred rounds of ammunition.

Tuff talked Hill into surrendering to officers. No one was injured, although police said Hill fired shots at responding officers.

Hill pleaded guilty in DeKalb County Superior Court to charges that included aggravated assault and burglary and was sentence to 20 years in prison.

Antoinette Tuff, who did not respond to requests for comment, dedicates “Prepared for a Purpose” first to God and then to her son Derrick, who she says is the first man in her family to graduate college.

“You are a beautiful miracle,” she writes, “and I am so proud God is using you to his Glory.”

Antoinette Tuff praises her son’s independence in several passages of the book, but he takes issue with her physical description of his legs as “useless and curled up beneath him” and other observations he found hurtful.

In one instance she writes, “There were many days when I’d watch Derrik hobble around or stare at the sky with his broken eyes.” In another: “One day when Derrick was younger and surrounded by therapists, I closed my eyes and formed a picture of him as a grown-up. I saw him on a street corner, in tattered clothes, leaning on a cane and begging for bread.”

Derrick Tuff said he was shocked and disappointed when he discovered how he’d been portrayed.

“This deeply saddens me because the image of independence I built was being torn down and I couldn’t do anything to prevent it.”

He wishes his mother had written more about his spirit of determination.

“It could’ve potentially motivated people to overcome their challenges,” he said.

Although he has to work harder because of his disabilities, Tuff said it has never occurred to him to quit or expect others to do what he can do for himself.

“My motto in life is, ‘where there’s a will, there’s a way’,” he said. “I constantly look for alternative ways to do things to minimize the help that I have to receive. I don’t believe in semi-dependency. I believe in self-sufficiency.”

Tuff said he can cook and dress himself. He can also catch the bus and the train without help.

He said he was the one who learned about the Louisiana Center for Blind, toured the campus, applied and graduated from there in 2011.

“She did assist me with some steps in the process, but I was in the driver’s seat when it came to decisions about my education,” he said.

Tuff also took exception to his mother’s account of his relationship with his father.

“She said that I said, ‘Daddy never loved me. He just tolerated me’,” he recalled. “I never said that. I said that my father didn’t know what to do with me because I wasn’t what he expected.”

His mother on the other hand was wonderful.

“She made sure that I had everything I needed,” he said. “She always supported me.”

Their relationship, however, began to change around age 18 when his father left.

“She clung tighter,” he said. “She wanted me to be her life partner.”

On the day of the shooting, “she said that I was hanging out with friends. I was actually going furniture shopping with my fiancé.”

Tuff met Kimberly Greer at Shamrock Middle School in Tucker. They reconnected in 2013 and have been together since. He maintains that Antoinette Tuff didn’t want anyone to know he was living with Greer “because it wasn’t right in the eyes of God.”

In 2014, Tuff, Greer and her daughter left Atlanta to live in Little Rock, Arkansas, where he believed he’d have a better chance finding work. Two years ago, Greer gave birth to Tuff’s son.

The couple hopes to launch a nonprofit — Project HIDE — to help people with disabilities excel personally and professionally.

“This has always been my goal in life,” Tuff said. “I’ve always been passionate about helping individuals with disabilities pursue independence.”

A big part of that is owning his disabilities, he said. But it’s also about moving beyond that and doing whatever it takes to live life fully and independently.

That’s the story he wishes his mother had told.