The article presents the results of historical-pedagogical analysis of the creative heritage of progressive educators, associates and followers of K. Ushinsky, who laid the scientific foundations of pedagogical mastery and made a significant contribution to updating the teacher's professional training. In order to obtain objective data on the selected problem of research, a set of interrelated methods was used: general scientific (historical-pedagogical analysis, synthesis, generalization, comparison), which became the basis for the study of procedural-content aspects of the development of ideas of teacher’s pedagogical mastery in the theory and practice of education in the investigated period. It was found out that the teachers of the late XIX and early XX centuries. with their scientific works laid the fundamental theoretical foundations of the development of ideas of pedagogical mastery; scientifically substantiated the ways of improving the teacher’s professional training; interpreting professional skills as a pedagogical phenomenon, elevated to the level of art and science. Pedagogical mastery was defined as individual creativity, based on knowledge of patterns and mechanisms of pedagogical process, which allows analyzing independently pedagogical phenomena, to find new teaching ideas, conclusions, principles in the theory and practice of teaching. The main feature of pedagogical mastery the teachers considered pedagogical culture and humanistic orientation of the teacher. Scientists have identified a number of criteria for assessing pedagogical mastery: the ability of the teacher to have the pedagogical technique necessary for the effective use of the system of methods of pedagogical influence; knowledge of a teacher related to the pedagogy of sciences (psychology, physiology, anthropology, ethics, etc.), which help the teacher to develop attention, memory, imagination, will, and other qualities in their pupils. Instructors, scientists distinguished the features of the teacher-master: the sincere love for children, the steadfastness of attention, patience, perseverance, diligent work, love for work, the gift of words, pedagogical tact, constant professional self-improvement, the desire to find the perfect methods of work. An important prerequisite for the achievement of pedagogical mastery was the pedagogical abilities and pedagogical vocation of man.