Hematopoietic stem cells give rise to various blood cell types with diverse functions, although these different cell types harbor essentially identical genome sequences. The basis for this cell type diversity is the establishment of specific gene expression patterns through transcription factor regulation. Transcription factors recognize and bind to specific nucleotide sequences in target genes and recruit chromatin modifiers to alter the epigenetic status of these genes, thereby controlling their expression. Dysregulation of these processes can cause diseases such as leukemia. Due to rapid advances in high-throughput experimental techniques including chromatin immunoprecipitation-sequencing (ChIP-seq) and RNA-seq, the study of transcription factors is now entering a new era. In this review, we update the current knowledge of developmental pathways in myeloid cells, particularly mononuclear phagocytes (i.e., monocytes/macrophages and dendritic cells), and the transcription factors known to be required for their development. We subsequently provide an overview of the cooperative and antagonistic mechanisms by which the myeloid transcription factors regulate their target genes, with an emphasis on chromatin biology.