The curse apparently ended on October 29, 2008, when the Philadelphia Phillies won the 2008 World Series, a year and four months after a statuette of the William Penn figure atop City Hall was affixed to the final beam during the June 2007 topping-off of the Comcast Center, currently the tallest building in the city.

The curse had gained such prominence in Philadelphia that a documentary film entitled The Curse of William Penn was produced about it.

Atop Philadelphia City Hall stands a statue of William Penn, the city founder and original proprietor of the then-British colony of Pennsylvania (meaning "Penn's Woods"). For many decades, a "gentlemen's agreement" stated that the Philadelphia Art Commission would approve no building in the city which would rise above this statue. This ended in March 1987, when a modern steel-and-glass skyscraper, One Liberty Place, opened three blocks away. One Liberty Place is taller than City Hall by 397 feet (121 m), rising 945 feet (288 m) in height compared to the height of Penn's hat on city hall, 547 feet (167 m). The measurement of the height of City Hall is usually rounded to 548 feet (167 m), which matches the career number of home runs hit by Phillies Hall of Fame third baseman Mike Schmidt. Its sister skyscraper, Two Liberty Place, at 848 ft (258 m), soon followed.

Philadelphia sports teams had enjoyed a run of success. Major League Baseball's Philadelphia Phillies won the 1980 World Series and the 1983 National League pennant; the National Hockey League's Philadelphia Flyers won back-to-back Stanley Cups in 1974 and 1975, and were a regular presence in the finals (1976, 1980, 1985, and 1987); the National Football League's Philadelphia Eagles appeared in Super Bowl XV in 1981, losing to the Oakland Raiders; and the National Basketball Association's Philadelphia 76ers won the championship in 1983, as well as making the finals in 1977, 1980, and 1982. Before 1980, the Phillies had appeared in only two other World Series, in 1915 and 1950, and the Eagles had won no NFC conference championships since the 1966 agreement that had created the Super Bowl, while the 76ers won NBA titles in both Philadelphia and in their previous incarnation, the Syracuse Nationals. Construction on One Liberty Place began in 1985, two years after the last championship season in Philadelphia. However, losses in 1977, 1981, and 1985 were also attributed to the "Curse of the Inauguration."

Unlike other "curses" that seem to strike particular teams, such as the Boston Red Sox's Curse of the Bambino, the Chicago White Sox's Curse of the Black Sox (both of which seem to have been lifted), the Detroit Lions' Curse of Bobby Layne and the Chicago Cubs' Curse of the Billy Goat, this curse, as well as the Curse of the Inauguration, have said to have struck four professional teams in the same city and is sometimes extended to include other sports.

After One Liberty Place opened, Philadelphia's franchises began a pattern of narrow but spectacular failures to win a world championship. The Flyers lost the Stanley Cup Finals twice, in 1987 to the Edmonton Oilers in seven games, two months after One Liberty Place opened and in 1997, in a four-game sweep by the Detroit Red Wings. The Phillies lost the 1993 World Series in six games to the Toronto Blue Jays, with the Series ending on Joe Carter's walkoff 3-run home run. The 76ers lost the 2001 NBA Finals to the Los Angeles Lakers in five games. The Eagles lost three straight NFC Championship games from the 2001 through 2003 seasons, before finally breaking through after the 2004 season and reaching Super Bowl XXXIX, only to lose to the New England Patriots by three points. However, the losses in 1993, 1997, 2001, and 2005 have also been manifestations of what John Smallwood of The Philadelphia Daily News called the "Curse of the Inauguration," though it dates back to 1977. In fact, the only years that Philadelphia's franchises played for championships after One Liberty Place opened were years that presidents were inaugurated, except for the Flyers in 1987.

In addition, losses in semifinal rounds had occurred eight times since the opening of One Liberty Place, including five by the Flyers, in 1989, 1995, 2000, 2004 and 2008. The 2000 team was one win away from a Stanley Cup Finals appearance, after leading the eventual champion New Jersey Devils 3-1 before losing three straight (including Games 5 and 7 at home), the 2004 team lost Game 7 of the Eastern Conference Finals to the eventual champion Tampa Bay Lightning, and the 2008 team lost to their cross-state rival and eventual champion Pittsburgh Penguins in five games. The Eagles accounted for the other three conference-final losses; they lost the NFC Championship Game (the winner of which meets the winner of the AFC's corresponding game in the Super Bowl) three years in a row from 2001 to 2003, thus becoming the first NFL team to do this in either conference since the Dallas Cowboys of 1980–1982, losing the last two at home after posting the best record in the NFC. No other team in NFL history had lost back-to-back conference title games at home since the NFL began its practice in 1975 of awarding home-field advantage in postseason play based on regular-season record.

Some believe the curse manifested again on December 19, 2004. The Eagles clinched home-field advantage for the NFC playoffs, but wide receiver Terrell Owens suffered a fractured fibula and severe ankle sprain, which was expected to end his season. Even so, the Eagles won the NFC Championship Game 27-10 over the Atlanta Falcons, breaking their triple NFC Championship losing streak. However, the Eagles lost 24-21 to the New England Patriots in Super Bowl XXXIX on February 6, 2005, despite Owens' return against medical advice. Donovan McNabb threw three interceptions after having had only eight in the entire regular season, and was speculated to be sick with the flu, even to the point that McNabb allegedly vomited during the Eagles' final offensive run. This loss also seemed to be attributed to the inauguration curse.

The curse was sometimes also extended to include Bensalem-Township-based thoroughbred racehorse Smarty Jones, who saw his bid for horse racing's Triple Crown disappear when he finished second by one length in the 2004 Belmont Stakes after decisive victories in the Kentucky Derby and Preakness Stakes.

Although the curse was not generally thought of as extending to college sports, two Philadelphia-based college basketball teams, the St. Joseph's Hawks and the Villanova Wildcats, which had very successful seasons in 2004 and 2006 respectively, failed to reach the Final Four of the NCAA Basketball Tournament. Both were eliminated in the fourth-round Elite Eight matches, with St. Joe's, first seed in the East Regional, losing in a close match to Oklahoma State, and Villanova, first seed in the Minneapolis Regional, falling to eventual NCAA-champion Florida. Villanova won the national championship in 1985, two years before the Liberty Place opening, but has not since. A third Philadelphia team, the Temple Owls, also failed to reach the Final Four five times due to losses in the fourth round (1988, 1991, 1993, 1999, 2001).