Non-thermal plasma has been proposed as a promising technique for the reformation of fossil fuel into cleaner fuel. Despite recent achievements in the economic and technical development of plasma-assisted reforming techniques, a better understanding of thermochemistry and electron-induced chemistry is required to optimize the performance of the relevant systems. We study the relative importance of electron-induced chemistry and thermochemistry for C5H12 (model gasoline) activation and products formation using a temperature-controlled dielectric barrier discharge (DBD) reactor. Important mechanical insight is obtained from the comparison between high-temperature and low-pressure conditions under similar reduced field intensities. In a tested range of background temperatures (303 < T < 623 K), we found that the conversion of C5H12 in the DBD depended only on electron-induced chemistry for the Ar/C5H12 and He/C5H12 mixtures, while it was affected by both electron-induced chemistry and thermochemistry for the N2/C5H12 mixture. However, the consecutive reactions from the initiation to the product always depended upon the corresponding thermochemistry for a given temperature. Due to an enhanced electron density and electron energy in the Ar/C5H12 and He/C5H12 DBD, increased C5H12 conversion was observed when compared to N2/C5H12. More importantly, cleaner products were produced from the Ar/C5H12 and He/C5H12 DBD because He and Ar were not involved in the product formation reaction pathways. We also found that extensive thermochemical involvement is favorable for enhancing the performance of plasma-assisted C5H12 reforming. Our findings may not only be useful for a greater understanding of the plasma-assisted reforming process but also helpful in designing a cost-effective plasma reformer.