The 4-year-old girl is the child of Biden's son, Hunter, who settled a years-long court battle over child support in June.
"This is not a political issue, it's a family matter. Jill and I only want what is best for all of our grandchildren, including Navy," Biden said.
The president said his son is working with the child's mother to foster a relationship that is "in the best interests of their daughter, preserving her privacy as much as possible going forward".
Speaking at an event at the White House in April, Biden noted that he was "crazy" about his six grandchildren, adding that he spoke to them every day.
Some Republicans and Democrats have criticized Biden's past decision not to acknowledge his seventh grandchild.
(Reporting by Jasper Ward; Editing by Cynthia Osterman)
