[1] In the November 2014 election for District 11 in the Arizona House of Representatives (Pima and Pinal counties), Leach successfully ran alongside fellow Republican Mark Finchem.

[5][6] In 2019, Leach voted for a bill expanding so-called "junk" health insurance plans in Arizona that do not protect against pre-existing conditions.

[8] In 2019, Leach sponsored legislation that would give unrestricted power to the Arizona attorney general to rewrite the ballot text of citizen voter initiatives.

Leach said that he sponsored the Republican-supported measure due to his opposition to the voter-approved initiatives that authorized medical marijuana and raised the state minimum wage to $12.

[11][12][13] In 2021, Leach supported legislation that made it easier to purge Arizona voters from the early voting list.

[14] In 2021, Leach sponsored legislation that would block any Arizona county or municipal government from banning so-called gay "conversion therapy.