Legendary acting coach Harry Mastrogeorge just turned 91 years old. That means for over five decades the celebrated instructor has been asserting his conviction that acting is a mentality, a state of mind with students such as Ray Liotta, Heather Graham, Melanie Griffith, Bryan Cranston, Daryl Hannah, Djimon Hounsou, and Brit Marling. In turn, many of his students talk about the trust they’ve learned to have in themselves under his tutelage. 

In his video “The Four Muscles of Acting,” Mastrogeorge taps into the simplicity of his teachings. However, he clarifies, “Simplicity doesn’t mean easy. It can be very challenging to maintain simplicity, especially for adults.” 

His basic premise is this: “Acting is a state of mind. It’s not a theory, it’s not a method, it’s not a technique, it’s not a process, it’s not a procedure. It’s a state of mind. It’s about priorities.”

To become an accomplished actor, he encourages his students to exercise four distinct muscles:


1. Childlike Innocence

Mastrogeorge works very hard with performers to revive their childlike innocence, as he believes it always exists, although it often gets buried under several layers. He maintains that all the acting greats have the ability to tap into this invaluable resource. After all, he attributes innocence to keeping a performance feeling natural and real. And the more actors focus on innocence, the more productive they’ll be.


2. Imagination 

Imagination, Mastrogeorge insists, is “infinite and limitless.” “How dare some acting teachers, some directors say, ‘Well, you can’t imagine that because you’ve never been there,’” he scoffs. One need not have personally suffered the tragedies of another to fully imagine the complexity and intensity of human emotion. “What they can say to you is, ‘You know, you haven’t used your imagination enough.”


3. Vulnerability

Similar to imagination, Mastrogeorge contends vulnerability is limitless. With various levels of vulnerability in the human experience as well as ongoing reasons to feel exposed or sensitive, there’s much to work with in this area.


4. Concentration

It’s important to clear away any and all distractions that are interfering with the work at hand. Most importantly, Mastrogeorge argues, “The best actors focus on the story.” 

By zeroing in on these four muscles, he insists that natural law is on the actor’s side—practicing and exercising them allows a performer to become “stronger and more proficient.”


On the other hand, Mastrogeorge considers two mind frames to be cancer to quality acting:


1. Concern about Results

“Concern about results, product, presentation, good, bad, right, wrong, approval—that’s a terrible thing to take into an audition with you,” he insists. Focusing on these aspects of acting will always distract a person from what matters most—which is, of course, the four acting muscles.


2. Subjectivity

A performer’s personal opinions, while they may be valid, have the potential to work against the goal at hand. For example, limiting thoughts like, “I don’t have enough time,” or “I don’t have enough information” can serve as effective barriers to a natural performance. More accomplished actors will take ahold of the material with the mind frame, “I absorb.” By fully embracing whatever is given, Mastrogeorge says, “You’re going to understand it much deeper, much better, and much more accurately.”

In a nutshell, Mastrogeorge contends acting is a “game of pretending.” And to be a successful actor, a performer needs to have “the hide of a rhinoceros and a heart of a baby. That’s key; that’s the secret.” Harry Mastrogeorge sticks as close to Stanislavsky as possible and recommends actors read Stanislavsky’s An Actor Prepares