In order to reduce carbon dioxide emissions, sustainable energy sources such as bio-oils have been pursued as alternatives to fossil oil. Bio-oil is produced through the pyrolysis of biomass and is later upgraded to remove oxygen in order to make the oil usable. This series of experiments aimed to determine the effects of pyrolysis temperature, wood particle size, and use of CaO powder to reduce char on the quality and quantity of bio-oil produced by the pyrolysis of Hinoki (Japanese Cypress) wood in a fixed bed reactor. The oil produced under these conditions was analyzed using gas chromatography–mass spectrometry (GC-MS) in order to determine if there was any notable difference in the oil composition. Based upon modeling of the results using an experimental design, surprisingly, all three factors had significant effects based on statistical analysis, with CaO having the greatest impact. As temperature and particle size decreased, bio-oil yield increased. Additionally, as more CaO was added, the bio-oil yield increased. None of the parameters had any discernible effect on the char amount. The composition of the bio-oils produced in each trial varied in accordance with the parameters chosen. Higher temperature greatly increased the acidity of the oil while decreasing the amount of ketones while lowering the yield. The mechanism on why the calcium oxide impacts the bio-oil yield is a topic of future research.