This study strove to investigate the effect of boar age on conventional and non-conventional quality traits of fresh and liquid-stored semen. Sixty boars were allocated into 3 groups: 8–12 months (young); 24–36 months (adult); and 48–60 months (senior). Ejaculates were divided into two parts; the first one was assessed in native state while the second one was extended in the Androstar Plus extender containing gentamycin, stored at 5 °C and evaluated following 72 h. Young animals presented with a significantly lower sperm motility (p < 0.01), membrane and acrosome integrity (p < 0.0001), and mitochondrial activity (p < 0.0001) against adult boars. Significantly higher levels of free radicals and tumor necrosis factor alpha (p < 0.001), interleukin 1 and 6 (p < 0.0001) were found in young boars in comparison to adult boars. The assessment of liquid-stored semen revealed a significantly lower sperm motility, membrane, and acrosome integrity (p < 0.0001) in young boars when compared to adult boars. Moreover, Clostridium difficile, Escherichia coli, Pseudomonas aeruginosa, and Rothia nasimurium remained in liquid-stored semen obtained from young boars, while Corynebacterium sp. and Escherichia coli continued to be identified in samples collected from adult boars. In conclusion, age contributes to the overall quality of fresh as well as liquid-stored boar semen.