The game, held on February 3, 2008 at University of Phoenix Stadium in Glendale, Arizona, was a rematch of the final game of the regular season. In that contest, the Patriots won 38–35 to complete the first perfect regular season since the 1972 Miami Dolphins team, and the first one since the league expanded to a 16-game regular season schedule in 1978. Thus, New England entered Super Bowl XLII as 13 to 14-point favorites.

As is always the case, the league considered several other cities before settling on the Phoenix area. In this case, the process was of special interest because the league considered holding Super Bowl XLII in New York City or Washington, D.C. as a symbol of the recovery from the September 11, 2001 attacks. New York City's bid did not go far. Aside from the obvious climatic concerns, there were issues with finding a suitable stadium. Proposed renovations to the 1970s-vintage Giants Stadium were still being disputed amongst the various parties. (Giants Stadium lacked a roof, as did both of New York City's baseball stadiums.) Also, the City of New York and the New York Jets failed to make a deal to build a new West Side Stadium (which, according to the initial plans, would have been built with a roof.) During the years since the Super Bowl XLII bid fell through, Giants Stadium has been demolished. Its replacement, New Meadowlands Stadium, bid for and was awarded Super Bowl XLVIII.

Washington DC's bid proved to be more viable. The DC area had a relatively new (albeit roofless) stadium, FedEx Field, and DC's winter weather (although still potentially problematic) is milder than New York's.

In the end, the process boiled down to three finalists: Washington, DC; Phoenix; and Tampa. NFL owners finally chose what is now known as University of Phoenix Stadium in Glendale, Arizona as the site for Super Bowl XLII during their October 2003 meeting in Chicago, Illinois. In subsequent years, Raymond James Stadium in Tampa was chosen as the site for Super Bowl XLIII and the West Side Stadium was briefly designated as the venue for Super Bowl XLIV. (However, Super Bowl XLIV was moved to Miami when it became clear that the new stadium in New York City would not be built in time for the February 2010 game.)

The kickoff for the game was at 4:32 p.m. MST (23:32 UTC). This was the first time a Super Bowl was played on a retractable natural-grass field surface; the University of Phoenix Stadium's removable surface is unique among American sports venues.

This was the second Super Bowl played in a retractable-roof stadium (designed by Peter Eisenman and HOK Sport). During the regular season, the home team decides 90 minutes before kickoff whether the roof would be open or closed, and an open roof must remain open unless weather conditions get worse. However, as a neutral site, the NFL controls the option to open or close without any restrictions. The first time this was employed was in Super Bowl XXXVIII at Reliant Stadium; the roof was open for pregame and halftime shows and closed during the game. Because there was rain in the forecast for Super Bowl XLII, the roof was closed for the entire day's activities.

During a February 6, 2007 ceremony with Arizona Governor Janet Napolitano, the NFL and the Arizona Super Bowl Host Committee unveiled the slogan "Who Wants It More?" along with its mascot "Spike the Super Ball" (an anthropomorphized football with sunglasses and sneakers) and a large "Super Bowl XLII Countdown Clock" at Phoenix Sky Harbor International Airport. The Super Bowl XLII logo was also unveiled, featuring the shape of the state of Arizona in red. The two horizontal white stripes in the middle represent the vertical lines on the University of Phoenix Stadium. The turquoise Roman numerals represent the Native American culture of Arizona. The red star represents the AFC and the blue star represents the NFC.

By the time the Patriots arrived at Super Bowl XLII, not only were they competing in their fourth Super Bowl since the 2001 season, they were already billed as one of the greatest teams in NFL history. They compiled a perfect 16-0 record (the first team to go undefeated in a 16 game regular season—the NFL expanded the regular season to 16 games in 1978), and set NFL records with 589 points scored (an average of 36.8 points per game), 75 total touchdowns, and a net differential of +315 points (they gave up 274 points, fourth best in the league). Some experts have suggested that the Patriots' 16-0 record is the culmination of a larger trend towards better records for top NFL teams since the league realignment in 2002.

The team was led by quarterback Tom Brady who won his first NFL MVP & NFL Offensive MVP award, throwing for a career high 4,806 yards and an NFL record 50 touchdowns (22 more than his previous best season), and just eight interceptions. His passer rating of 117.2 was the second-highest season rating in NFL history. One often-cited reason for Brady's improved numbers was the acquisition of receivers Randy Moss and Wes Welker. The Patriots acquired Moss, a nine-year veteran, from the Oakland Raiders for a fourth-round pick in the 2007 NFL Draft after Moss had, statistically, the worst year of his career (with 42 receptions for 553 yards and three touchdowns). With the Patriots, though, Moss caught 98 receptions for 1,493 yards and an NFL record 23 touchdowns, and was selected a first-team All Pro. The Patriots also gave the Miami Dolphins second- and seventh-round picks for Welker; Welker tied for the league lead with 112 receptions for 1,175 yards and 8 touchdowns and was named a second-team All Pro. Welker and Moss both earned votes for Offensive Player of the Year. Other major contributors to the Patriots' passing game included Donté Stallworth, who added 697 yards and three touchdowns, and tight end Benjamin Watson, whose 36 receptions totaled 389 yards and six touchdowns.

Running back Laurence Maroney was the Patriots' top rusher with 835 yards and six touchdowns, while Sammy Morris added 385 yards & 3 TDs, and Kevin Faulk had 265 yards. (Morris ended up on injured reserve midway through the season, and thus could not play in the Super Bowl.) Faulk was also a reliable receiver out of the backfield, catching 47 passes for 383 yards and a touchdown. The Patriots also had an offensive line that featured three players selected to the Pro Bowl, guard Logan Mankins, tackle Matt Light, and center Dan Koppen.