Much of the research on principal effectiveness has concluded that principals have minimal direct impact on student achievement. This study focused on direct one-on-one motivational interviews between a principal and nonproficient students aiming to improve the students’ motivation, positive academic behaviors, and math achievement. This randomized control trial built upon some of the major positive elements that Silva, White, and Yoshida (2011) established through their research with a small group of principals and students in a suburban community and enhanced it in multiple aspects as follows. The grade levels were from sixth to eighth. The study employed the use of a more established motivational interviewing protocol which can be defined as a collaborative, goal-oriented style of communication with particular attention to the language of change. The ANCOVA was used to determine whether there was a direct effect of principal motivation interview on student achievement, positive academic behavior, and motivation. In comparison to the control group, students in the experimental condition showed nearly significant gains in math achievement, homework completion and increased intrinsic motivation, and significant decrease on time spent on social media.