Cytotoxic CD8 T cells exert their antiviral and antitumor activity primarily through the secretion of cytotoxic granules. Degranulation activity and cytotoxic granules (perforin plus granzymes) generally define CD8 T cells with cytotoxic function. In this study, we have investigated the expression of granzyme K (GrmK) in comparison to that of GrmA, GrmB, and perforin. The expression of the cytotoxic granules was assessed in virus-specific CD8 T cells specific to influenza virus, Epstein-Barr virus (EBV), cytomegalovirus (CMV), or human immunodeficiency virus type 1 (HIV-1). We observed a dichotomy between GrmK and perforin expression in virus-specific CD8 T cells. The profile in influenza virus-specific CD8 T cells was perforin⁻ GrmB⁻ GrmA^+/− GrmK⁺; in CMV-specific cells, it was perforin⁺ GrmB⁺ GrmA⁺ GrmK^−/+; and in EBV- and HIV-1-specific cells, it was perforin^−/+ GrmB⁺ GrmA⁺ GrmK⁺. On the basis of the delineation of memory and effector CD8 T cells with CD45RA and CD127, the GrmK⁺ profile was associated with early-stage memory CD8 T-cell differentiation, the perforin⁺ GrmB⁺ GrmA⁺ profile with advanced-stage differentiation, and the GrmB⁺ GrmA⁺ Grmk⁺ profile with intermediate-stage differentiation. Furthermore, perforin and GrmB but not GrmA and GrmK correlated with cytotoxic activity. Finally, changes in antigen exposure in vitro and in vivo during primary HIV-1 infection and vaccination modulated cytotoxic granule profiles. These results advance our understanding of the relationship between distinct profiles of cytotoxic granules in memory CD8 T cells and function, differentiation stage, and antigen exposure.