Serotype K54 Klebsiella pneumoniae is one of the major serotypes causing invasive community-acquired (CA) bacteremia in Taiwan while limited studies reported. This study utilized a 9-year (2014–2022) bacteremia patients database from our hospital to analyze the clinical characteristics of patients infected with K54 K. pneumoniae and microbiologic features of corresponding strains comparing with those by K1 K. pneumoniae. During the study period, a total of 772 bacteremia inpatients infected by K. pneumoniae were screened. Among these, 33 isolates (4.2%) were identified as K54, while 97 (12.5%) were K1. Patients with K54 bacteremia more frequently had liver cirrhosis (p = 0.013) and a higher Charlson Comorbidity Index score (p = 0.044). Disease severity was greater in the K54 group, as indicated by a higher SOFA score (p = 0.002), whereas intra-abdominal infection was less frequent compared to those by K1 K. pneumoniae (p = 0.016). The 28-day mortality did not differ significantly between groups. The prevalence of hypervirulent strains and antimicrobial resistance profiles was similar between K54 and K1 strains. In subgroup analyses of K54 K. pneumoniae isolates stratified by CA and hospital-acquired (HA) infections, isolates from CA infections showed a higher prevalence of hypervirulent strains and lower levels of antimicrobial resistance compared with those from HA infections. In conclusion, K54 K. pneumoniae bacteremia patients were associated with greater comorbidity burden and disease severity than K1 K. pneumoniae infection. K54 K. pneumoniae isolates from CA and HA infections exhibited distinct microbiologic features, suggesting divergent evolutionary trends under different environmental pressures.