On CBS's "Face the Nation" Sunday, Duncan said when such effects will take place is unknown, but the across-the-board cuts will cause nationwide instability in the education system.
"And as you know, the vast majority of federal money goes to help vulnerable children, so whether it's children with special needs, whether it's poor children, whether it's adults in college who are doing work study programs, whether it's our babies we talk about in Head Start, we don't have any ability with dumb cuts like this to figure out what the right thing to do is," he said.
Duncan insisted that the sequester's effects are not being exaggerated, and said the cuts would lead to 70,000 less children in the Head Start program.
Duncan said school districts are already struggling and blamed Congress for not knowing what is going on in their local districts.
"We don't have to be in this situation. This is not rocket science. We could solve this tomorrow if folks had the will to compromise, to come to the table and do the right thing for children and to try and keep growing the middle class," he said.