The Mastery Rubric is a curriculum development and evaluation tool. It articulates the knowledge, skills, and abilities (KSAs) of a given curriculum, together with the developmental trajectory that learning these KSAs is intended to follow. Mastery Rubrics have focused on graduate and post-graduate curricula, and utilize the European Guild Structure for staging growth and development of KSAs. Bloom’s taxonomy is also essential for describing the performance, and performance levels, in each stage. A defining characteristic of the Mastery Rubric is the Master level: the Master is qualified, with evidence, to take a learner from novice through to Master. However, the transition from competent independent performer of a set of KSAs to Master is not addressed in any of the Mastery Rubrics to date. This article describes three levels through which any instructor can progress in order to generate evidence they are qualified at the Master level for any Mastery Rubric, even those that have already been published to include a (single) Master level. These three levels describe the evidence that can be observed to represent early, middle, and late Master capabilities in terms of teaching, and assessing learning, in students and trainees. Two new Mastery Rubrics (MRs) have recently been completed, and neither has a Master level: one for Bioinformatics (MR-Bi) and one for the Nurse Practitioner (NR-NP). Although this new Mastery Rubric for the Master Level (MR-ML) can be used with all of the existing Mastery Rubrics to characterize the development of the Master’s engagement with theories and practicalities of learning, we use the MR-Bi and MR-NP to illustrate how the MR-ML can work with these two new MRs, and how individuals in any field can compile their evidence of the specific abilities to diagnose problems exhibited by those at earlier stages, devise remediating activities for those problems, and assess the result.