Amish Shah defeated Marlene Galán-Woods, Rick McCartney, and Jonathan Treble in the Democratic primary for Arizona's 1st Congressional District on July 21. Galán-Woods and Shah led in endorsements and media attention. Incumbent David Schweikert (R) ran for governor of Arizona.

Having voted for former President Joe Biden (D) in 2020 and President Donald Trump (R) in 2024, the district was one of the most competitive in the country and a top Democratic target in 2026. Before the election, The Cook Political Report with Amy Walter, Inside Elections with Nathan L. Gonzales, and Larry J. Sabato's Crystal Ball all rated the 1st District a toss-up.

12 News' Kevin Reagan wrote, "Republicans have a significant advantage over Democrats in the party's number of registered voters in CD1. But the district has over 180,000 non-affiliated voters who could sway the election's outcome." AZ Central's Laura Gersony added that the district "has historically preferred more moderate political figures."

Galán-Woods was a former broadcast journalist. Her campaign website said she was "running for Congress to stand up to extremists and be a voice for all Arizonans. She will be the courageous, truthful leader Arizona’s first district deserves." Galán-Woods switched from the Republican Party to the Democratic Party in 2018. In 2024, she said, "I have always been pro-choice, pro-democracy, pro-climate. My values have never changed. What changed was the Republican party."

Shah was an emergency room physician. He represented the 5th District in the Arizona House of Representatives from 2023 to 2024 and the 24th District from 2019 to 2023. Shah's campaign website said that as a state legislator, Shah was an "independent voice working across party lines to put Arizona families first while standing up to extremist attacks on abortion and voting rights. In Congress, he’ll work to lower costs for hardworking Arizonans, protect Social Security, Medicare, and Medicaid, fight for abortion rights, and keep families safe."

Galán-Woods and Shah competed against each other in the district's 2024 Democratic primary, with Shah winning the primary with 23.5% of the vote and Galán-Woods placing third with 21.2%. Schweikert defeated Shah in the general election 51.9%-48.1%.

On May 4, 2026, the Democratic Congressional Campaign Committee added Galán-Woods to its "Red to Blue" program, which included strategic guidance, staff resources, training, and fundraising support. Elections analyst Nathan L. Gonzales said Shah could have a possible advantage with "residual name identification [that] could help him top a crowded primary field with a plurality of the vote once again."

Before the election, this was one of 58 open races for the U.S. House of Representatives in which an incumbent did not seek re-election. Across the country, 22 Democrats and 36 Republicans were not seeking re-election as of the July 21 primary. In 2024, 45 incumbents — 24 Democrats and 21 Republicans — did not seek re-election.