[1][2] Mattox worked on the Santa Fe Railroad as a conductor for over 20 years.
In 1924 he resigned from the railroad and took a full-time position managing the Hall Lumber Company in Winslow, Arizona.
Mattox had been a vice-president of the company for two years prior to accepting the full-time job.
[4] In 1911 he ran for the State House of Representatives for the seat from Navajo County.
[5][6] In May 1912, during the third special session of the legislature, Mattox introduced a resolution asking that Arizona ratify the Seventeenth Amendment to the United States Constitution.