Alvin Hubbard III of East New Market, Maryland faces up to 14 years in prison if he gets the maximum sentence on all charges.
He pleaded guilty to five counts of Operation of a Motor Vehicle Causing Death, one count of Vehicular Assault (2nd Degree) and one count of Vehicular Assault (3rd Degree).
Hubbard's pickup truck crossed the median on Route 1 and collided with the family's minivan in July 2018.
The family was returning from a trip to Ocean City, Maryland at the time.
In the indictment, investigators said neither drugs nor alcohol were involved in the crash, but that Hubbard operated his pickup truck in a criminally negligent manner.
The family's matriarch, Mary Rose Ballocanag, survived. Her husband Audie Trinidad of Teaneck, New Jersey, and their four daughters died in the crash.
Hubbard's pickup truck also hit a car driven by 24-year-old Brian Kern of Bethlehem, Pa. Kern survived, as did a passenger in Hubbard's truck.
In an interview, Kern said the crash site looked like a "war scene."
"Out of the corner of my left eye, I see this F-350 truck wildly swerving in the median through the grass, and I knew it was coming right for us," Kern said.