At least three types of B lymphocytes are important for providing memory in a humoral immune response: ‘classical’ memory cells that do not secrete immunoglobulin (Ig), long‐lived plasma cells (LLPCs) in the bone marrow, and ‘innate‐like’ B‐1 cells. In this review, our work on B‐lymphocyte‐induced maturation protein‐1 (Blimp‐1), a critical regulator of terminal B‐cell differentiation, is discussed in the context of current knowledge of all transcriptional controls that regulate these three types of B cells. Blimp‐1 is not required for formation of memory cells, but it is required for them to progress toward becoming plasma cells. Blimp‐1 is required for Ig secretion in plasma cells and in B‐1 cells. Induction of the activator X‐box‐binding protein‐1 and formation of µ‐secreted mRNA depend on Blimp‐1 in both cell types. Finally, even after their formation, LLPCs in the bone marrow continue to require Blimp‐1 for their maintenance.