LeBron James says watching his son Bronny make his college debut just five months after he suffered a cardiac arrest meant "everything" to him and his family.

Bronny James was found to have a congenital heart defect after suffering a cardiac arrest during a workout at the University of Southern California in July.

Having recently been cleared for full-contact practice, the 19-year-old made his debut for the Trojans on Sunday, collecting four points, three rebounds and two assists in an 84-79 overtime loss to Long Beach State.

After helping the Los Angeles Lakers win the inaugural NBA in-season tournament on Saturday, LeBron James returned home to take in his son's debut, later describing it as a special moment. 

"It was everything for my family," the NBA's all-time leading scorer said. "It was just an emotional, draining day, from the time we all woke up to the time the buzzer hit zeros.

"That moment was everything for us. To be there, to see the first person out of our family, out of the James gang, grace a college campus and a college floor… that was pretty cool.

"I think the most important thing, who cares about the win or the loss, the kid was standing tall and standing strong at the end of the game.

"That is a blessing in its own right, and that is a win. He's won at life, and everything else at this point is extra credit."

James senior was back on the court himself on Tuesday, with his 33-point haul not enough for the Lakers as they returned to regular-season action with a 127-125 road loss against the Dallas Mavericks. 

The Lakers have two more road games this week, facing the struggling San Antonio Spurs in a double header before returning home to take on the New York Knicks next Monday.