The Washington Attorney General's Office serves over 230 state agencies, boards, commissions, colleges, and universities, as well as the governor and Legislature.

[10] As Attorney General, McKenna made the protection of consumers and businesses, the improvement of community safety and the advancement of open government his chief priorities.

He defeated former Insurance Commissioner and Democratic Senate candidate Deborah Senn in the November General election and was one of just a few Republicans to win statewide office in 2004.

[8] In his first year as attorney general, McKenna founded "Operation: Allied Against Meth", a program designed to reduce the drug's manufacture and use in Washington.

[2] The initiative included an increase in the law enforcement and prosecution personnel dedicated to cracking down on methamphetamine-related crimes, a statewide educational program to help prevent the use of the drug, and a legislative alliance devoted to improving Washington's meth problem.

Acting in this capacity, he helped lead cases against subprime lenders that resulted in the largest settlements in the history of American consumer protection lawsuits.

He received the support of two Democrats, State Auditor Brian Sonntag and Snohomish County Prosecuting Attorney Janice Ellis.

[15] In his second term, McKenna continued to be active in the National Association of Attorneys General, serving as co-chair on various committees and receiving the NAAG's Distinguished Service Award before becoming Vice-President of the organization in 2009.

[16] On March 22, 2010 McKenna announced that he was joining other Republican elected officials in a multi-state challenge to the constitutionality of a health care overhaul bill passed by US Congress and signed by President Obama.

[17] The ongoing legal battle grew into a 26 state coalition of plaintiffs, including McKenna, who maintained his original motivation to see the provision for mandatory purchase of private individual health-insurance plans by 2014 struck down for being unconstitutional.

When announcing his gubernatorial campaign, he said "We deserve a governor who will bring us a leaner, better-run state government that doesn't demand endless tax increases before it delivers results to its bosses, you the taxpayers.

Prior to a US Supreme Court ruling allowing such action; McKenna has proposed requiring out-of-state businesses that sell into Washington (including online and mail-order companies) to pay state taxes, even if they lack a physical presence there.

On May 20, 2021, McKenna joined a lawsuit against a capital gains tax signed into law by Washington governor and his 2012 gubernatorial opponent Jay Inslee.

[citation needed] As a general provision, McKenna would support legislation that would require parental notification before a minor obtains an abortion.