Oscar is the ninth child born to Charles Franklin Stevens and Olive Emily DeMill. He was good with horses and helped his father with round ups in Long Valley and into Kane County.

He married Eva Dennett on December 2, 1914 in the St. George Temple. They lived in Rockville where their first child, Carl was born. The little boy died of asphyxiation because his throat could not properly be cleared after his birth. They had two more children, Amanda and Alva born to them while they lived in Rockville. The family then moved to Hurricane where they had three more children, Ella, LaRue and Gwendolyn.

In 1924 while he was hauling lumber from Cedar Mountains down to Cedar City, he was struck with pneumonia and was unable to drive his team into town. He was taken to the hospital in Cedar and died there on September 29, 1924. He was buried in the Hurricane Cemetery.

Eva was left alone to raise their five daughters. Oscar's brother, Carlos did the best he could to help Oscar's wife and family. After her husband's death Eva went to Carlos and asked him to help find a companion for her. He found Israel Taylor Neilson in Cedar City who was a perfect stranger to Carlos. He told Israel that he had a wife for him and that he would bring him a picture of her and her daughters on a certain day. They met each other at Eva's parents house soon after that and Israel said to Eva's father, "Brother Dennett, how do you feel about me taking your daughter for a wife?" He answered, "Well if Carlos says it is alright, it's alright with me." Israel and Eva were married the next day in St. George. He had been married twice before he married Eva. He died on June 28, 1964 in St. George and was buried in the Cedar City Cemetery.