Mattie was a pioneer in the sport of rodeo, raising the status of performers through her own rodeo contracts. She was a daring trick rider known for her speed and for never losing her hat. As a bronc rider Mattie was never thrown and as a relay rider she was never outrun. She was one of the first inductees into the National Cowboy Hall of Fame. After marrying, Mattie turned her attentions to her ranch in South Dakota.