He appeared on ABC7 news Monday morning and said extending financial incentives to charters is about equity for all CPS schools.
Last week, the school board approved a plan to offer up to $6 million in grants to charter schools that adopt the extended calendar now instead of waiting until next school year.
Brizard said despite budget constraints, funding for the incentives for charters was set aside.
"(When) you are budgeting a school district, you look to invest," he said. "It's like when you pay your bills you look to see what you want to pay first and what you want to invest in. That's what we are doing. We are making money available, reducing the bureaucracy and funding things that we know are important to our schools."
The plan is to have all CPS schools to have longer school days next year. Nine schools have already started.
There is no indication how many charter schools will accept the offer.
A new report out Monday shows Iillinois schools that have longer days have students perform better in standardized achievement tests.
Mayor Rahm Emanuel said the report by the state Board of Education is proof that students in Chicago need to be in class longer.