The event aired via pay-per-view (PPV) and livestreaming and featured wrestlers from the promotion's Raw and SmackDown brand divisions.

For SmackDown's other main match, Bianca Belair defeated defending champion Asuka and Charlotte Flair in a triple threat match to win the WWE Women's Championship, after which, Iyo Sky cashed in her Money in the Bank contract and defeated Belair to win the title.

For Raw's two main matches, Seth "Freakin" Rollins defeated Finn Bálor to retain the World Heavyweight Championship and Cody Rhodes defeated Brock Lesnar in what was his most recent WWE appearance to date until he was named under the sex trafficking scandal involving Vince McMahon and a former employee.

This would subsequently be the final SummerSlam in which WWE was majority owned and controlled by the McMahon family before the company's deal with Endeavor was finalized on September 12, 2023, which saw WWE and Endeavor-owned Ultimate Fighting Championship subsequently merging to become divisions of a new jointly formed corporate entity called TKO Group Holdings.

[10] The event featured wrestlers from the Raw and SmackDown brand divisions, and in addition to airing on pay-per-view worldwide and the livestreaming services Peacock in the United States and the WWE Network in most international markets,[7] it was also the first SummerSlam to livestream on Binge in Australia after the Australian version of the WWE Network merged under Foxtel's channel Binge in January.

[11] Detroit area native, musician, and WWE Hall of Famer Kid Rock did the cold open for the event.

[15] Hours before WrestleMania 39 Night 2 began, CNBC reported via multiple sources that a deal between WWE and Endeavor, the parent company of Ultimate Fighting Championship (UFC) via Zuffa, was imminent.

The deal involved a merger of WWE with the UFC into a new publicly traded company, with Endeavor holding a 51% stake.

[16] The sale was confirmed the next day on April 3[17] and was finalized on September 12, with WWE merging with the UFC to become divisions of TKO Group Holdings.

[18] SummerSlam took place on the same night as the boxing match between Jake Paul and Nate Diaz in Dallas, Texas.

[22] On the Raw after WrestleMania 39, for unknown reasons, Brock Lesnar viciously attacked Cody Rhodes before both were set to participate in a tag team match.

[29] At Money in the Bank, Seth "Freakin" Rollins successfully defended the World Heavyweight Championship against Finn Bálor after Judgment Day stablemate, Damian Priest, who had won the men's Money in the Bank ladder match earlier that night, accidentally distracted Bálor.

[29] At Night of Champions, Asuka defeated Bianca Belair to win the Raw Women's Championship.

Prior to the presentation, WWE official Adam Pearce requested Belair not to interrupt, who stated that she wanted a rematch for the title.

[34] On July 21, a triple threat match between Asuka, Belair, and Flair for the WWE Women's Championship was scheduled for SummerSlam.

[25] Jey would also leave The Bloodline on the June 16 episode of SmackDown, where he attacked Reigns and Sikoa, choosing to stand by his brother Jimmy's side.

During the match, both were involved in a high spot in which they performed simultaneous springboard clotheslines at each other from opposite sides of the ring and collided in midair, which went viral across social media.

After an argument between Sheamus and LA Knight, WWE official Adam Pearce named the two as the first entrants.

In the closing moments, Gunther performed a top rope splash and then followed up with a lariat and a powerbomb on McIntyre to retain the title.

[48] In the penultimate match, Asuka defended WWE Women's Championship against Bianca Belair and Charlotte Flair.

Flair drove Belair's face into the middle turnbuckle and performed a top rope moonsault onto both opponents for a nearfall.

After the match, Dakota Kai joined Bayley in celebrating with Sky in the ring in her first appearance in WWE since she tore her ACL.

The hooded man revealed himself to be Jimmy Uso, who superkicked Jey and then rolled him back inside the ring.

Reigns then speared Jey through a table that was set up in a corner of the ring to retain the title and recognition of Tribal Chief.

[54] Cody Rhodes opened the following episode of Raw and stated that he respected Lesnar after his gesture following their match at SummerSlam.

This prompted World Heavyweight Champion Seth "Freakin" Rollins to come out and challenge Rhodes.

Bálor attacked Rollins, which led to one-half of the Undisputed WWE Tag Team Champions, Sami Zayn, coming out for the save.

Rhodes, Rollins, and Zayn then challenged Judgment Day to a six-man tag team match.

Sky and Bayley continued to attack Flair and Asuka while Dakota Kai reminded the crowd who their new WWE Women's Champion was.

[61] Later that year, The Usos reunited with Reigns as well as Sami Zayn and began to feud with Sikoa's iteration of The Bloodline, which since added Tama Tonga, Tonga Loa (formerly known as Camacho), and Jacob Fatu, whom the trio had emerged victorious at Survivor Series: WarGames in a 4-on-4 WarGames match.