As American football teams can consist of many "squads" inside the one unit, Mark Cornaga said his son is a "slot receiver" on offence, which involves receiving the ball from the quarterback near the line of scrimmage to make short runs forward bursts amongst tacklers like a flanker would in rugby.
For the defence, Cornaga is a defensive back, similar to a rugby fullback.
"As in the NFL, teams have specialist positions and [defensive back] is where Cullen excelled," said Mark Cornaga.
His son would take the one-point conversions after touchdowns and scored 27 of them this season, including a perfect seven from seven attempts in one game.
"Like the pro teams, they are big on statistics and watch a lot of game video," said Mark Cornaga.
In total, Cornaga scored 33 points for the season, including the 27 kicking points, while making 10 tackles and two field goals one a 42 yard effort and the other from 32 yards out.
He also made one interception and created three "touch backs" where the ball goes into the opposition end-zone and they cannot advance it, so the kicking team gets possession back.
Mark Cornaga said his son's goal now is to get a "full ride" scholarship ie all expenses paid to an NCAA Division 1 University.
"His favourite college team is UC Berkeley the California Golden Bears and has attended some of their games and would love to attend this prestigious university, " said Cornaga senior, who went to the University of San Francisco in the 1990s.
The younger Cornaga grew up loving American football and is a fan of the Atlanta Falcons in the NFL.
"He can tell you about all the teams in the NFL, name over 200 players and what position and team they play on. Has always watched games on ESPN."
The family had previously lived in the States in 2003-2004.