Dareus, who donated $125,000 through his foundation to fund the building, said he was touched by the emotional response he received.
"It is one thing to give money to something and hope for the best; it is quite something else to witness your efforts and see the gratitude and thankfulness of not just the children, but the whole community, for doing what you're doing," the 28-year-old Dareus said, per the Florida Times-Union.
"To receive their blessings and hear their words of appreciation directly was something I could have never imagined several years ago. Their gratitude and happiness was overwhelming and showed me that what I am doing is going to have a tremendous impact on their lives."
In addition to funding the building, Dareus' efforts will pay for teachers' salaries and school supplies.
Dareus has visited Haiti in back-to-back offseasons to reconnect with his late father's homeland and give back through his partnership with "Hope for Haiti."
Haiti was ravaged by a devastating earthquake in 2010 as well as damages sustained following the 145 miles-per-hour winds from Hurricane Matthew in 2016.
"I promised my mom that I would support Haiti in any way I could and now I am using my platform to keep my promise," the 6-foot-3, 331-pound Dareus said. "It's a beautiful country with incredible people and children who need help. I want to make sure I do everything I can to lift them up.
"This is just the beginning of what we're looking to accomplish here. I plan to come back after next season to see the new school and decide what else I can do to continue to build a legacy of hope for Haiti."
The three-classroom building will be called the Marcell Dareus School Wing at the Christ-Roi Primary School of Cammy.