Yantis was born in Kentucky, and worked as a cotton farmer near what was then Orland, Oklahoma Territory until he met outlaws Bill Doolin and George "Bittercreek" Newcomb.
It is believed that he first met Newcomb, who at the time, was involved romantically with Yantis' sister.
Yantis was with the gang when they committed bank robberies in Caney, Indian Territory on October 14, and Spearville, Kansas on November 1, both in 1892.
Ford County, Kansas Sheriff Chalkley Beeson and Deputy US Marshal Tom Hueston trailed Yantis to the McGinn farm near Dodge City, but he had already left.
The lawmen nursed his wounds, and took him to a hotel in Orlando, where he died that next day.