Dolan appeared Thursday with Mayor Bill de Blasio at a Bronx parochial school.
The two men met with students. Dolan said that the 1,700 new pre-k seats would be found between the Archdiocese of New York and the Archdiocese of Brooklyn.
The spots would be available to children of all faiths.
But Dolan stopped short of endorsing de Blasio's plan to fund the program by raising taxes on wealthy New Yorkers.
Gov. Andrew Cuomo has proposed finding money in the state budget instead. The tax hike needs the support of Albany.
Dolan said he would leave it to the politicians to determine the funding.