Yost was elected attorney general of Ohio on November 6, 2018. He assumed the office on January 14, 2019.

In January 2014, it was reported that there were 11 public entities considered under Ohio law to be “unauditable,” which included two community schools and several townships throughout the years between 2010 and 2013. Yost’s chief deputy officer, Bob Hinkle, spearheaded an audit of the two school districts. One school, Greater Heights Academy had four years of unauditable books from 2006 through 2009. Four individuals associated with the school were indicted in November 2013 for wire fraud, mail fraud and conspiracy to launder money for defrauding the school of more than $400,000. Another school, Lion of Judah, had its principal indicted in February 2013 for illegally funneling $1.2 million of public funds to a private business run by the principal, while the school’s former treasurer received a prison term of 2 years for the theft of federal education funds. Hinkle said in January 2014 that both schools were closed. Hinkle also supported reform. "If their office is declared unauditable, hopefully the next time they stand for election, they won’t be re-elected or put back into office," he said in an interview. "And if they’re appointed, my hope would be that the board that governs their activity would put people in place who can do what they need to do."

In 2011, the Ohio State Legislature passed legislation creating JobsOhio, a private nonprofit economic development firm tasked with attracting businesses to the state. A major source of funding for the firm is the $100 million in profits that come from the state's liquor operations. Prior to the creation of JobsOhio, those profits went to the state's general fund. The legislation creating the organization allows for a yearly audit by a private auditor, but controversy arose as the $100 million was previously public money.

In March 2013, Yost, arguing he had the authority to audit the money, subpoenaed the company's records. In response, Gov. John Kasich (R) and the legislature rushed through legislation that stated the liquor money is legally private money and does not fall under a public audit. Yost, who said he would not have supported the original legislation, sent lawmakers a letter on March 19, stating, “I urge you to tread cautiously. While there have been no indications of misdealing, the potential for self-dealing or other mischief exists sometime in the future. This office’s audit will help protect against the real possibility of human failings."

The issue of the private/public status of JobsOhio was before the state Supreme Court. Lawyers on both sides of the suit addressed the court on November 6, 2013. A bipartisan group made up of Democratic lawmakers, progressive activists and conservative lawyers sought to have the money publicly audited, arguing that it was unconstitutional for public money to be invested in private companies without public oversight. The state, meanwhile, argued that the plaintiffs do not have standing to sue.

On June 10, 2014, the Ohio Supreme Court ruled in favor of the state in a 5-2 decision. The ruling stated that the activists who brought the lawsuit against JobsOhio did not have standing and lacked a "personal stake" in the case.

Delaware County Auditor (1999-2003)

Yost served as auditor of Delaware County from 1999 to 2003.

Yost was the 32nd Ohio state auditor, serving from January 2011 to January 2019. He won re-election in November 2014.

School audits

In January 2014, it was reported that there were 11 public entities considered under Ohio law to be “unauditable,” which included two community schools and several townships throughout the years between 2010 and 2013. Yost’s chief deputy officer, Bob Hinkle, spearheaded an audit of the two school districts. One school, Greater Heights Academy had four years of unauditable books from 2006 through 2009. Four individuals associated with the school were indicted in November 2013 for wire fraud, mail fraud and conspiracy to launder money for defrauding the school of more than $400,000. Another school, Lion of Judah, had its principal indicted in February 2013 for illegally funneling $1.2 million of public funds to a private business run by the principal, while the school’s former treasurer received a prison term of 2 years for the theft of federal education funds. Hinkle said in January 2014 that both schools were closed. Hinkle also supported reform. "If their office is declared unauditable, hopefully the next time they stand for election, they won’t be re-elected or put back into office," he said in an interview. "And if they’re appointed, my hope would be that the board that governs their activity would put people in place who can do what they need to do."

JobsOhio

In 2011, the Ohio State Legislature passed legislation creating JobsOhio, a private nonprofit economic development firm tasked with attracting businesses to the state. A major source of funding for the firm is the $100 million in profits that come from the state's liquor operations. Prior to the creation of JobsOhio, those profits went to the state's general fund. The legislation creating the organization allows for a yearly audit by a private auditor, but controversy arose as the $100 million was previously public money.

In March 2013, Yost, arguing he had the authority to audit the money, subpoenaed the company's records. In response, Gov. John Kasich (R) and the legislature rushed through legislation that stated the liquor money is legally private money and does not fall under a public audit. Yost, who said he would not have supported the original legislation, sent lawmakers a letter on March 19, stating, “I urge you to tread cautiously. While there have been no indications of misdealing, the potential for self-dealing or other mischief exists sometime in the future. This office’s audit will help protect against the real possibility of human failings."

The issue of the private/public status of JobsOhio was before the state Supreme Court. Lawyers on both sides of the suit addressed the court on November 6, 2013. A bipartisan group made up of Democratic lawmakers, progressive activists and conservative lawyers sought to have the money publicly audited, arguing that it was unconstitutional for public money to be invested in private companies without public oversight. The state, meanwhile, argued that the plaintiffs do not have standing to sue.

On June 10, 2014, the Ohio Supreme Court ruled in favor of the state in a 5-2 decision. The ruling stated that the activists who brought the lawsuit against JobsOhio did not have standing and lacked a "personal stake" in the case.