This study investigates the morphological and functional differences between the char produced after pyrolysis and hydrothermal liquefaction (HTL) of sugarcane bagasse termed pyrochar and hydrochar, respectively. The char materials were activated with KOH at 800 °C and doped with SnCl2·2H2O salt to produce an environmentally friendly catalyst (i.e., SnOx-char) to be further evaluated as a catalyst for glucose conversion in ethanol media. Activation increased the surface area and microporosity development of the chars, thus enabling more effective tin doping. Hydrochar had a lower surface area with no micropore development but exhibited more carbonyl functional groups on the surface of up to 65% content compared to pyrochar. The pyrochar showed superior catalytic performance because of the higher tin doping and more pronounced microporous carbon structure. Effects of glucose ratio (1:1–1:10), reaction temperature (140–220 °C), and time (1–8 h) on the production of 5-methyl furfural (MF) from glucose using pyrochar were systematically explored. This work achieved over 32.8% MF yield at 200 °C after 8 h of processing catalyzed by the tin-doped pyrochar in ethanol. It is demonstrated that the char produced by pyrolysis and HTL differs in its characteristics and catalytic activity performance, with the pyrochar being more suitable for the one-step catalytic conversion of glucose into MF.