Cathelicidin LL-37, an antimicrobial peptide (AMP) of the innate immune system, wards off bacterial infections. Recent research has identified plenty of biological functions of AMPs beyond their antimicrobial activity, including antioxidant, self-renewal, and procollagen properties, making them valuable for antiaging products. In this study, we assessed the antiphotoaging potential of cathelicidin LL-37 fragments and KR-12 analogs using human immortalized keratinocytes (HaCaT) and human dermal fibroblasts (HDF). Our results reveal that these peptides can modulate ultraviolet-radiation-induced photodamage, exhibiting anti-inflammatory and antioxidant properties. Notably, we proved the immune modulation effects of LL-23. Additionally, these peptides promote cell migration and collagen synthesis, inhibit glycation, and suppress melanin production. We propose that the antiphotoaging effects exhibited by LL-37 fragments and KR-12 analogs are related to the alleviation of inflammation, and we attempt to elucidate the possible underlying mechanisms. These findings support their efficacy as antiaging agents in dermatological applications.