An increasing interest in novel wine productions is focused on non-Saccharomyces yeasts due to their potential in improving sensory profiles. Although Kluyveromyces marxianus has been originally isolated from grapes and its enzymatic activities are used in oenology, rarely it has been used as co-starter. The K. marxianus Km L2009 strain has been characterized here and selected as a co-starter both at laboratory- and winery-scale fermentation. The Km L2009 strain showed growth of up to 40 (mg/L) of sulfites and 6% (v/v) of ethanol. Gas chromatographic analysis demonstrates that wines produced by mixed fermentation contain remarkably higher quantities of free monoterpenes and aliphatic esters than wines produced only by commercial strains of Saccharomyces cerevisiae. Differences in the volatile organic compound composition produced sensorially distinct wines. In light of these results, it is possible to state that even within the K. marxianus species it is possible to select strains capable of improving the aromatic quality of wines.