"I get to greet 417 smiling, skipping, laughing, children every day," Niblock added. "It energizes me, it gives me that sense of purpose."
The 42-year-old father of two said that he decided to continue to work, despite being diagnosed with the incurable disease around 11 months ago, because he wanted to be an example for his students and teach them a lesson about life.
"I want children to understand curve balls," Niblock said. "No matter what is thrown your way ... if a kid powers through or makes the most of something later because of knowing me, that'd be great."
ALS, a rare and incurable nervous system disease, is characterized by progressive muscle weakness, according to the ALS Association. The disease gained widespread awareness after baseball legend Lou Gehrig succumbed to it in 1941.
Rather than try and conceal the changes to his speech and mobility, Niblock is hoping to use his diagnosis to teach children about ALS and raise awareness for it by creating age-appropriate videos with the school's headmaster, Adam Rohdie. Spencer’s daughter Kate is a student at Greenwich Country Day School.
"You want to arm children, with 'You can do something, you can make a difference yourselves,'" Rohdie told ABC News. "And Andrew's helped us do that."
Three of Niblock's young students described him as "really nice," "caring," and "very happy."
Niblock told ABC News that if there is one thing that he wants children to take away from witnessing his battle with ALS, it is that "hope's resilient."
"Hope can drive you forward," he added. "And I hope ... that the kids see that, and run with it."