Born in West Virginia,[1][2] one of 15 children in his family, Bonnifield attended Allegheny College in Meadville, Pennsylvania.
[1] He then went to Ottumwa, Iowa, where he practiced law until he "with his young wife crossed the plains in 1861, going to Red Bluff, California".
[1] Following a January 1869 riot against Chinese laborers, Bonnifield "was successful at having the charges dropped while pointing out that mob action was not the solution to the 'Chinese problem'".
[1][4] There, Bonnifield "became a strong advocate of woman suffrage in an era when conservative resistance continued to block enactment in Nevada".
[1] Following his service on the court, Bonnifield went to Tonopah, Nevada, during a silver rush there, and practiced law, accumulating a fortune in stock speculation, which was later lost.