The lawsuit alleges the NFL hid the dangers to players of repeated blows to the head, The New York Times reported Wednesday. Riddell Inc., the manufacture of helmets for the NFL, is also being sued for "negligent" design.
The action was filed Wednesday in California Superior Court in San Diego. The family is seeking unspecified compensatory and punitive damages, the Times said.
The lawsuit, the report said, alleged the NFL "propagated the myth" that repeated collisions between players, some of whom suffered neurological injuries, "are an acceptable, desired and natural consequence of the game."
The NFL issued a statement that its attorneys would respond "appropriately through the court."
Seau, 43, died last May is a self-inflicted gunshot to the chest. Tests on Seau's brain determined he suffered from chronic traumatic encephalopathy, a condition usually found in post-mortem examinations of people who suffered multiple concussions or other head injuries.
More than 4,000 retired NFL players or their families have filed suit against the NFL related to long-term problems related to head injuries. The NFL has generally requested the cases be consolidated in U.S. District Court in Philadelphia, the Times said.