UFL

In September 2023, Axios reported that the XFL was in advanced talks with the USFL to merge the leagues prior to the start of their 2024 seasons. On September 28, 2023, the XFL and USFL announced their intent to merge with details surrounding the merger to be announced at a later date. The merger would also require regulatory approval. In October 2023 the XFL filed a trademark application for the name "United Football League". On November 30, 2023, Garcia announced via her Instagram page that the leagues had received regulatory approval for the merger and were finalizing plans for a combined season to begin March 30, 2024.

The merger was formally announced on Fox NFL Sunday on December 31, 2023. The eight surviving teams were announced the following day on College GameDay, along with the alignment; the XFL and USFL will survive as separate conferences. Daryl Johnston would note in February that maintaining the XFL and USFL conferences as separate entities was designed to build an on-field rivalry between the two brands and to give the winner of the league's championship "bragging rights." President/CEO Russ Brandon would later say that the league would be looking at expansion shortly, while Defenders defensive coordinator Gregg Williams revealed plans to expand to 12 teams by 2025 and to 16 teams by 2026. In a May 2024 interview, Johnston stated that he did not anticipate any relocations for 2025.

The 2024 UFL season began on March 30, 2024, with a matchup between the 2023 XFL champion Arlington Renegades and the 2023 USFL champion Birmingham Stallions. It concluded with the 2024 UFL Championship Game between the Stallions and the San Antonio Brahmas on June 16 in St. Louis.

The UFL exceeded internal expectations for the 2024 season, with Fox Sports executive Eric Shanks commenting that, though the league still lost money, it was "ahead of the expected pace" in terms of achieving self-sustenance. Television viewership rose substantially compared to the previous season as separate leagues, while ticket sales in most cities declined, prompting the league ownership to shift investment toward local ticket sales teams.

The 2025 UFL season began on March 28, 2025 and concluded with the 2025 UFL Championship Game on June 14 in St. Louis, where the DC Defenders defeated the Michigan Panthers. In November 2024, the UFL announced it was officially initiating a team expansion process, and was welcoming proposals from potential markets interested in professional spring football.

In an interview with Randy Karraker prior to the 2025 UFL Championship Game, Brandon indicated that the league had reached the point of being a going concern and that players, agents and coaches now had enough confidence in the league that it was not at risk of failure in the short term, effectively guaranteeing a 2026 UFL season. Overall television ratings and attendance went down in most markets (with the exception of the Michigan Panthers, who made substantial gains), which prompted the firings of ticket sales directors and vice presidents of business operations in Arlington, Houston and Birmingham, three of the UFL's most consistently underperforming markets. The decline in television ratings was not enough to cause alarm for league executives, who remained satisfied with the results, but did prompt reconsideration of the league's start date, which followed the USFL model of starting several weeks after the end of the NFL season (whereas the XFL traditionally drafted off the end of the NFL season and began play the weekend after the Super Bowl). Reports circulated that the UFL would also shift the date of the 2025 UFL draft, moving it from July to September to capitalize on roster cuts made by NFL teams after their preseasons conclude, allowing UFL teams to use their draft picks more effectively on players more likely to sign immediately.

Responding to a July 23, 2025 report that the entire USFL Conference would be relocated to other cities by early August in time for the 2026 season, the UFL neither confirmed nor denied the "unauthorized speculation". One of the alleged host venues that the report claimed would be hosting a team—Albertsons Stadium in Boise, Idaho—released a statement denying the stadium would host the UFL in 2026 but that it was a possibility for the future. Sources in Lexington, Kentucky, another one of the cities mentioned in the report, also denied that they had heard from anyone in the league about the supposed relocations.

On July 31, 2025, the league announced the addition of another private equity firm, Impact Capital, to the league's ownership group, with its owner Mike Repole serving as the league's new director of business operations; Repole stated that he had purchased a large minority stake in the league. As part of the same announcement, Repole confirmed that one of the league's eight teams would be relocating to Historic Crew Stadium in Columbus, Ohio and that the league would remain at eight teams for 2026, with two to four teams relocating which had not yet been decided. Birmingham was the first of the four reported teams to be addressed when Repole responded to fans' Save the Stallions campaign by stating it would be given one final chance to increase its ticket sales, aiming for 5,000 season ticket deposits and 15,000 tickets per game. Positive response to the Stallions deposit drive prompted Repole to confirm the team's return for 2026, admitting the move was a test of how the Stallions fan base would respond. In Michigan's case, Repole stated that he was "trying" to keep the team in the state but that his stadium options were undesirable.

On October 3, 2025, the UFL announced that the Michigan Panthers, Memphis Showboats and San Antonio Brahmas would not return for the 2026 season. Repole cited Michigan in particular as a return candidate for 2028 when AlumniFi Field opens. San Antonio's shuttering, which was personally ordered by Repole, was a complete surprise, as the UFL had already renewed the stadium lease for the Alamodome when the team's shuttering was announced.

On October 7, 2025, the UFL announced their new teams for the 2026 season; the Columbus Aviators (playing at Historic Crew Stadium in Columbus, Ohio), the Louisville Kings (playing at Lynn Family Stadium in Louisville, Kentucky) and the Orlando Storm (playing at Inter&Co Stadium in Orlando, Florida). They also announced the relocation and rebrand of two of their legacy teams; the former Houston Roughnecks would revert to their Houston Gamblers name and play at Shell Energy Stadium, and the former Arlington Renegades would revert to their Dallas Renegades name and play at Toyota Stadium.

Among other changes were the formal dissolutions of the XFL and USFL conferences, and the planned institution of territorial rights to college players, something the XFL had explicitly rejected.