[6] During his tenure as governor, Runnels secured funding for a new statehouse in Jackson, restructured the state militia, signed a ban on the importation of enslaved people for auction and oversaw the formation of sixteen new counties in the land seized from the Chickasaw Indians.

[7] A devoted Jacksonian Democrat, Runnels angered his political allies when he refused to order the state militia to support and arm vigilantes who killed and maimed dozens of white and black people suspected of inciting a slave rebellion during the summer of 1835.

On the other hand, more conservative voters and Whigs accused Runnels of verbally condoning vigilantism and preventing the militia and local law enforcement officials from suppressing extralegal violence.

Facing criticism from Whigs and many Democrats over the affair, Runnels narrowly lost his reelection bid and left office in November 1835.

[8] In 1838, Runnels was appointed president of the newly chartered Union Bank in Jackson, placing him in deeper conflict with other Democrats.

[13] Described as excitable and volatile, his narrow defeat in the 1835 Mississippi gubernatorial race was partially attributed to an emotional outburst against one of his opponents during which he used some very harsh and unparliamentary language.