[15] By intervening, the Attorney General's office made itself a part of the cases and argued that the plaintiffs' group, Advocates for Individuals with Disabilities, exceeded its legal authority and was not allowed to collect fees on these types of lawsuits.

In September 2016, a judge agreed to allow the Attorney General's office to intervene and consolidated the cases while also preventing Advocates for Individuals with Disabilities from filing new lawsuits.

After the ruling, Brnovich said "Arizona is not going to tolerate serial litigators who try to shake down small hardworking businesses by exploiting the disability community.

"[17] As attorney general, Brnovich undertook efforts in the area of consumer protection and advocacy, including the opioid epidemic.

According to Brnovich, Arizona was the first state to obtain restitution directly for consumers as part of a settlement with GM related to faulty ignition switch claims.

[23][22] In 2018, Brnovich announced that Volkswagen had agreed to settle a consumer fraud lawsuit with the State of Arizona for $40 million over its diesel emissions scandal.

[25] In October 2020, Brnovich announced a $71 million settlement with Ticketmaster that provided refunds to consumers who purchased tickets to live events in Arizona that were cancelled, postponed, or rescheduled due to COVID-19.

Shortly after taking office, Brnovich sued the Barack Obama administration for its Clean Power Plan, a carbon emission reduction initiative intended to reduce climate change.

"[42] The constitutionality challenge included an additional charge against the Board of Regents for continuing to provide in-state tuition for Deferred Action for Childhood Arrivals (DACA) recipient students.

[44] On April 9, 2018, the Arizona Supreme Court ruled in a 7–0 decision that state colleges and universities could no longer provide in-state tuition to individuals who were covered under DACA.

[45] That same day, the Arizona Board of Regents announced that they would no longer be providing in-state tuition for DACA students in upcoming semesters.

Brnovich alleged that a hotel project in downtown Tempe was improperly given a tax exemption because it was being built on tax-exempt university property.

[47][48][49] Representatives from ABOR and ASU defended the practice, saying they collect a payment from the hotel in lieu of taxes and that extra money helps the school general revenue.

[49][51] In 2021, a Maricopa County Superior Court judge ruled that Brnovich had to pay almost $1 million of legal fees to the Arizona Board of Regents.

[52] After the U.S. Supreme Court ruled that prohibitions on same-sex marriage were unconstitutional, Brnovich instructed Arizona's child safety agency that only married heterosexual couples should be allowed to adopt children.

[59][60] In one case, Masterpiece Cakeshop v. Colorado, the Supreme Court of the United States ultimately ruled 7-2 in favor of a religious baker who refused to bake a cake for a same-sex couple, finding the Colorado Civil Rights Commission violated the bake shop owner's free exercise of religion.

[61] In the other case, Brush & Nib v. City of Phoenix, the Arizona Supreme Court found the City of Phoenix's Human Relations Ordinance could not be used to force or punish a business owner to create art (in this case custom calligraphy wedding invitations) that violates a person's "sincere religious beliefs.

[63] In November 2015, Brnovich filed a special action with the Arizona Supreme Court to remove Republican Susan Bitter Smith from her position on the Arizona Corporation Commission over allegations that she had violated state conflict-of-interest laws because of her work in the private sector involving cable companies that are overseen by the office she was elected to.

A more complete report, withheld until Brnovich left office in January 2023, found that none of the allegations of election fraud had merit.

The Capitol Times stated: "It's his non-political work in the area of law enforcement and consumer protection and advocacy that is earning Brnovich a lot of praise.

"[18] Brnovich worked with Representative Shawnna Bolick to draft a bill allowing human and sex trafficking victims to take civil action against their perpetrators.