Per one of the agreed parts of the 1970 AFL-NFL Merger, the NFL began planning to expand from 26 to 28 teams. On June 15, 1972 Seattle Professional Football Inc., a group of Seattle business and community leaders started by Herman Sarkowsky and Ned Skinner, announced its intention to acquire an NFL franchise for Seattle. Almost 2 years later on June 4, 1974, the NFL awarded the group an expansion franchise. On December 5, 1974, NFL Commissioner Pete Rozelle announced the official signing of the franchise agreement by Lloyd W. Nordstrom, representing the Nordstrom family as majority partners for the consortium. Nordstrom died of a heart attack on January 20, 1976, just months before the Seahawks played their first game.

In January 1996, Seahawks owner Ken Behring announced that he was moving the franchise to Los Angeles, where the team would play at Anaheim Stadium. Behring claimed safety concerns (specifically the building’s structural integrity in the event of an earthquake) as his reason for breaking the team’s lease with King County. However, seismologists found Behring’s claims to be unproven. Also, the Los Angeles area is even more earthquake prone than Seattle. Although Behring moved the team’s operations to Anaheim, his plans for a full move were scuttled when lawyers discovered that the Seahawks were locked into the Kingdome through 2005. Having seen his effort to permanently relocate the franchise thwarted, Behring decided to sell. A potential buyer was found in Microsoft co-founder Paul Allen, who reached an agreement to buy the club but only if a new stadium would be built. After funding a special state-wide election for stadium financing, a new stadium for the Seahawks was passed and Allen purchased the team.

For the 2000 – 2001 seasons the Seahawks moved to Husky Stadium while their new stadium was being built. Big changes were afoot in 2002. When the Seahawks left Husky Stadium at the end of the 2001 season they were part of the AFC West, but when they moved into Seahawks Stadium they were now part of the NFC West. It was originally called Seahawks Stadium but was renamed Qwest Field on June 23, 2004 when telecommunications carrier Qwest acquired the naming rights. CenturyLink Field has earned a reputation as one of the loudest stadiums in the NFL. It is in the Guinness World Record books for being the loudest stadium in the world. The seating decks and partial roof trap and amplify exceptional amounts of noise and bang it back onto the field. This noise contributes to increased false start penalties since opposing offenses can miss audibles and the snap count. From 2002 through 2012, there have been 143 false-start penalties on visiting teams in Seattle, second only to the Minnesota Vikings.

Pete Carroll took over as the Seahawks head coach in 2010. On the morning of January 9, 2010, Carroll reportedly came to agreement with the Seahawks on a 5-year contract that would appoint him as head coach. He was officially hired as the Seahawks head coach on January 11. Carroll’s fourth season, 2013, was his greatest level of success in the professional league. His Seahawks finished the regular season with a sterling 13-3 record, placing them on top of the NFC conference for their first time since 2005. The ’05 Seahawks produced an identical record, excelled through the playoffs, and into the Super Bowl for the first time in franchise history.

Super Bowl XLVIII was an American football game between the American Football Conference (AFC) champion Denver Broncos and National Football Conference (NFC) champion Seattle Seahawks to decide the National Football League (NFL) champion for the 2013 season. The Seahawks defeated the Broncos 43–8, the largest margin of victory for an underdog and tied for the third largest point differential overall (35) in Super Bowl history with Super Bowl XXVII (1993). It was the first time the winning team scored over 40 points, while holding their opponent to under 10. This became the first Super Bowl victory for the Seahawks and the fifth Super Bowl loss for the Broncos, the most of any team. The game was played on February 2, 2014, at MetLife Stadium at the Meadowlands Sports Complex in East Rutherford, New Jersey, the first Super Bowl played outdoors in a cold-weather city and the first Super Bowl to be played on a February 2.