After the resignation of Bill Northey, Kim Reynolds appointed Naig to succeed him in March 2018.

[3] He served in this role until March 2018, when Northey was appointed Under Secretary for Farm Production and Conservation at the United States Department of Agriculture, at which point governor Kim Reynolds appointed Naig as Iowa Secretary of Agriculture to fill the vacancy left by Northey.

[2][4] Naig won election to a full term as Iowa secretary of agriculture in November 2018, defeating Democratic challenger Tim Gannon 50% to 47%.

[6] In the election, Naig received the backing of the Farm Bureau as well as companies like John Deere and Monsanto.

[7] He has often spoken in favor of biofuels to combat climate change, rather than switching to electric vehicles.