On September 26, 2015, Greitens announced his candidacy for governor of Missouri as a Republican.
Shortly after a June 30, 2016, quarterly deadline for filing campaign contributions, he received the largest ever single contribution in a Missouri campaign, $1.975 million, which meant he did not have to reveal it until October, months after the primary.
The source was a previously unknown Superpac, "SEALS for Truth".
SEALS for Truth had received the money from the American Policy Coalition (APC), another Superpac, on the same day APC received the entire amount.
Greitens had assured voters he intended to increase transparency while reducing corruption in state politics as a campaign focus.
APC, about which there was almost no information online, was headed by Ohio lawyer David Langdon, who had incorporated it in Kentucky in 2015.
Between the 2010 election cycle and early 2015, at least 11 groups connected to Langdon spent at least $22 million on ballot initiatives against abortion and same-sex marriage and on federal and state elections around the country, as tabulated by the Center for Public Integrity.
On March 12, 2017, the St. Louis Post Dispatch and The Kansas City Star editorial boards published a joint editorial criticizing Greitens for "secret fundraising and secret spending" and for tactics such as ordering that "[s]ecurity staffers block reporters from getting close to him".
In 2018 Missouri Attorney General Josh Hawley, a Republican running for the U.S. Senate, announced the opening of an investigation of Greitens's 2016 campaign financing.

Greitens won the August 2 Republican primary with 236,250 votes (34.6%) to businessman John Brunner's 169,425 (24.8%), Lieutenant Governor Peter Kinder's 141,498 (20.7%), and former Speaker Catherine Hanaway's 136,350 (19.9%).
Democrat-turned-Republican Greitens faced Republican-turned-Democrat Chris Koster in the general election on November 8, 2016, and won with 51.3% of the vote to Koster's 45.4%.

On April 28, 2017, the Missouri Ethics Commission fined Greitens's campaign $1,000 for violating state campaign ethics rules regarding campaign disclosure.
Greitens did not contest the fine.
On September 26, 2015, Greitens announced his candidacy for governor of Missouri as a Republican. Shortly after a June 30, 2016, quarterly deadline for filing campaign contributions, he received the largest ever single contribution in a Missouri campaign, $1.975 million, which meant he did not have to reveal it until October, months after the primary. The source was a previously unknown Superpac, "SEALS for Truth". SEALS for Truth had received the money from the American Policy Coalition (APC), another Superpac, on the same day APC received the entire amount. Greitens had assured voters he intended to increase transparency while reducing corruption in state politics as a campaign focus. APC, about which there was almost no information online, was headed by Ohio lawyer David Langdon, who had incorporated it in Kentucky in 2015. Between the 2010 election cycle and early 2015, at least 11 groups connected to Langdon spent at least $22 million on ballot initiatives against abortion and same-sex marriage and on federal and state elections around the country, as tabulated by the Center for Public Integrity. On March 12, 2017, the St. Louis Post Dispatch and The Kansas City Star editorial boards published a joint editorial criticizing Greitens for "secret fundraising and secret spending" and for tactics such as ordering that "[s]ecurity staffers block reporters from getting close to him". In 2018 Missouri Attorney General Josh Hawley, a Republican running for the U.S. Senate, announced the opening of an investigation of Greitens's 2016 campaign financing.
Greitens won the August 2 Republican primary with 236,250 votes (34.6%) to businessman John Brunner's 169,425 (24.8%), Lieutenant Governor Peter Kinder's 141,498 (20.7%), and former Speaker Catherine Hanaway's 136,350 (19.9%). Democrat-turned-Republican Greitens faced Republican-turned-Democrat Chris Koster in the general election on November 8, 2016, and won with 51.3% of the vote to Koster's 45.4%.
On April 28, 2017, the Missouri Ethics Commission fined Greitens's campaign $1,000 for violating state campaign ethics rules regarding campaign disclosure. Greitens did not contest the fine.
Eric Greitens