When he was eight years old, Sensei John was hurt badly by a neighborhood bully in his hometown of Brooklyn, New York. For seven months he studied karate for survival. The next time the bully fought him, he did not win the fight, but he did earn the bully's respect. He was not bothered again.

At age 14, his serious training began. At age 19, he earned his black belt from his father and began teaching at Nassau Community College. He initiated an adult class two times a week, and then later began teaching four and five-year-old children at the Naval Base next door, an experience that helped him appreciate the importance of both patience and simplicity.
In May of 1984, he enlisted in the United States Air Force. During his four years of military service, Sensei John developed a martial arts dance act by setting karate to music and performing nationwide as an Air Force entertainer. Throughout this time, he continued teaching privately to both civilians and military personnel.

Upon honorable discharge in March of 1988, he worked as a security officer for the New York Daily News and performed his martial arts dance act at the Apollo Theater in Harlem. Appearing on seventy-two episodes of Club MTV, he also parlayed his skills into that of a choreographer. After leaving the Daily News, he began teaching at the Apple Health and Sports Club and opened his own school in Ridgefield, New Jersey.

However, it was to last only six months. Iraq invaded Kuwait, and Sensei John, an Air Force reservist, was put on active duty and stationed in Germany as part of Operation Desert Storm. He served as a dietitian and helped wounded and sick soldiers recover their health. When he returned to the United States, he found the Apple Health and Sports Club gone, but was able to re-establish his Ridgefield school and started teaching at New York's Vertical Club.

By 1991, Sensei left the Vertical Club to concentrate on his New York students, including students at Capitol Records. He was also recruited as a fitness consultant at the Jeff Martin Studios where he worked until it closed in 1994. He heard through one of his students that Reebok Sports Club/NY was constructing a new facility and in search of a karate system that employed all the aspects of traditional karate. In 1995, having found great satisfaction in helping to improve the lives of many of New York's "movers and shakers" through karate instruction, Sensei applied to Reebok, and after an intensive eight-month interview process was accepted on the basis of his answer to the question: "Why do you want to teach at the Reebok Sports Club/NY?" His reply: "Because the members of your club are the leaders of society. If I want to make a positive impact on society, I need to teach them."
In 1997, Sensei John produced an event known as "Universal Harmony Day" on Columbus Avenue in front of ABC. The goal of the event was to raise awareness and money to help fight child abuse. Sensei John was helped by many of his students, some of whom were celebrities and wanted to support such a worthy cause.

From 1997 to 2000, Sensei John's "Philosophy of the Week" was heard every Friday morning on Z-100 radio: his community service was to reach out to New Yorkers and give them something to think about and discuss.

In 2001 he became the first American to teach karate at New York's prestigious Nippon Club, a Japanese social organization. His goal was to give back to Japanese culture by bridging the gap in U.S./Japanese relations through his martial arts teaching.

In 2003, for the first time in the history of Shorinjiryu, Sensei John's Harmony By Karate school was featured in Blackbelt Magazine.
In 2005, as part of the series, "The National Body Challenge", Sensei John was featured on the Discovery Health channel teaching national radio disc jockey Zach Martin for a six month period. It was the first time to show life transformation through the martial arts on television.
In 2006, through Sensei John's efforts and the support of ABC television, World Blackbelt, Tiger Claw magazine, Parent Guide magazine, Battle of Atlanta newspaper, September 11th was declared Universal Harmony Day. ABC television sponsored and produced a thirty second PSA commercial featuring Sensei John announcing September 11th as Universal Harmony Day. This holiday was presented as a day for giving and a celebration of humanity.

In 2008, Sensei John formed the partnership with African organization, MaAfrica Tikkun. 
He and his family personally hosted two young women from a poor South African community for two months, and provided intense physical and spiritual training that they brought back to their village.

In 2009, Sensei John published his first book, Philosophy of the Week which is used as a inner guide tool for his students as well as the general public. Sensei John also directed and produced a CNN commercial to promote Harmony By Karate.

In 2010, Sensei John Mirrione's National Stop Bullying Campaign was launched on Oprah Radio Saturday December 11th, 1:15 PM on the Derrick Ashong Show. The year-long, national, public-awareness and philanthropic effort, designed to support Stop bullying causes, began in Chicago in December 2010. Sensei John is travelingl to 9 cities across the country to share with school children his inspiring story and teach them about building inner strength through meditation and philosophy.
In 2011, Sensei John Mirrione set a new world record. Under the watchful gaze of observers from Record Holders Republic, he performed the world's slowest one- arm, bare-knuckle push up on a stone block. Posted on AOL News/ABC News Sensei John Vists numerous cities helping hundreds of children on his national tour.

In 2015, as a result of the Sensei John's efforts traveling to 17 cities the Harmony Power Foundation was formed through generous pro bono work of companies AIG and Verizon. The charities mission is "stand up to bullying and stand for human equality."
In the same year, Sensei John did a TV Show with legendary Deepak Chopra on bullying and the Harmony Power Foundation's mission. This show aired worldwide on numerous media outlets building awareness on this global crisis.

In 2016, Sensei John realized that policies in the schools were very reactive recognizing children when they misbehaved. He developed an award program that will impact millions of children. It is the Harmony Power Award program. Children throughout the state of New Jersey will be recognized for the efforts promoting harmony in the world thought art, music, dance, community service, etc.. This concept was submitted as a NJ Bill by Assemblywoman Sumpter and will be part of NJ's "Week Of Respect."

Also in the same year, Sensei John was sought out by General Electric to be its special guest speaker for GE's Annual Global Leadership Conference with representatives of 70 countries present. He empowered, motivated, and inspired it leaders.

Throughout his career, Sensei John, with the support of family, students and friends has won numerous karate tournaments, been published in many magazines and newspapers (please see the Publications section of the website), has appeared on many television and radio programs, and made two trips to Japan for in-depth study of its culture and martial arts. His goal is to continue help improve society through his philosophy and martial arts teachings.