Haden played one season in the
World Football League for the
Southern California Sun, which allowed him to go to attend school at
Oxford University under his
Rhodes Scholarship. His decision to go to the
United Kingdom for schooling hurt his NFL possibilities and he dropped to the 7th round of the
NFL Draft.
Haden made the
Los Angeles Rams' roster in 1976 as the third quarterback behind
James Harris and
Ron Jaworski. When both Harris and Jaworski were injured, Haden was pressed into duty in the fifth game of the season. He responded by playing mostly mistake-free football, letting running backs
Lawrence McCutcheon and
John Cappelletti shoulder the offensive load, passing only occasionally. He led the Rams to the NFC Western Division title and a 14-12 upset of the defending NFC champion
Dallas Cowboys in the opening round, but the Rams fell to the
Minnesota Vikings in the
NFC Championship Game.
Even as Haden played well, the Rams wanted experience and a stronger arm at the quarterback position for the
1977 NFL season. Both Harris and Jaworski left for other teams as free agents, so the Rams decided to give creaky veteran
Joe Namath a chance. Namath started the first four games, but it was evident his knees couldn't take it anymore, so the Rams went back to Haden. Haden led the Rams to eight victories in the last 10 games, winning the NFC West and making the playoffs once again. Their first-round opponent was once again the Vikings at home, but the Rams lost 14-7 in the
Mud Bowl.
Haden was rewarded with the starting position from day one in 1978. The Rams started fast, going 8-0, but tailed off to 12-4, still winning their third straight NFC West Division title. Haden threw a pair of touchdown passes and led the Rams to a 34-10 victory against the Vikings in the first round of the playoffs. The
Dallas Cowboys, however, walloped the Rams 28-0 in the
1978 NFC Championship Game on their way to the
Super Bowl.
Haden began the 1979 season as the starter, but a broken finger midway through the season sidelined him in favor of
Vince Ferragamo. Ferragamo ended up leading the Rams to
Super Bowl XIV.
Because of Rams' coach
Ray Malavasi's policy of giving an injured starter his job back, Haden began the 1980 season as the starter with Ferragamo as the backup. Haden was largely ineffective in the first two games and was benched while Ferragamo passed for a then Rams-record 30 touchdown passes.
Ferragamo, however, bolted the Rams for the
Canadian Football League. Haden once again went into the 1981 season as starter, but was injured midway through that season before deciding to retire.