The objective of this study was to evaluate the effect of the trainer and the adopted daily work on the behavior and performance of horses of the Mangalarga Marchador breed on a horse farm and in racetracks in northern Minas Gerais State, Brazil. Twenty equines and nine trainers from four farms and three competition events of the breed were observed. The experiment was divided into two stages. In the first stage, the animals were observed together with their trainer on the farm, during the daily work, and the behavior reactions were recorded based on scores. The duration of training and the behavior told by the trainer of the animal were recorded in scores. The second stage happened in three competitions of the breed in agricultural fairs. The same observations were made on horse farms, including the behavior of the animal, before and after the trial, as well as the emotional state in the same period. For data analysis, multivariate statistics were used based on the principal components and factor analysis, using the statistical software R (version 3.3.2). From the data analyzed, it was verified that the variables embouchure, behavior and voice of the presenter, and reward and incentive in the competition influenced the reactivity of the animal. Variables of human behavior in training influenced the animal behavior variables in training. The behavior of the trainer and the form of the training, as well as the fact that the trainer is the presenter, interfered in the behavior of the horses on the horse farm and in the competitions, resulting in safer animals. However, the need for time adaptation and training management is necessary for the whole man × animal relation to get better rankings in the race competitions.