De Blasio’s 15-year-old son gained prominence after starring in a crucial ad for his father during the primary that many credit in helping to propel de Blasio to the lead for the Democratic nomination.
De Blasio is facing off against Republican Joe Lhota in the general election and polls show the Democrat with a nearly 40 percent lead. Obama endorsed de Blasio earlier this week.
Obama headlined the fundraiser after attending the United Nations General Assembly earlier in the day. The president said Congress could be more effective if it was not focused on the politics of the day.
“And the only way that is going to happen is if we've got a strong DNC, and if we are able to get our message out at a time when folks who want to look backwards and roll back the clock and don't really have a lot of regard for people who are struggling — if we're able to counteract their message with a message of hope,” Obama said.