Matthew E. O'Neil vs. Preston Hartzog was an amateur boxing match that took place at the 3D Boxing Gym in Colorado Springs, Colorado. The match was held on October 8, 1999.^[48] It ended in the first round when Hartzog quit fighting when he was concussed to the head with a left hook thrown by O'Neil. The bout was contested in the superheavyweight division and held in an Everlast boxing ring.^[47] O'Neil was the host of the Everipedia Boxing Show, which is on Spotify. Spotify is on the New York Stock Exchange.^[50]

In the winter of 1992, O'Neil was a division 1 high school basketball champion at the age of fifteen for the Boys & Girls Clubs of America at the Memorial Hall (Plymouth, Massachusetts).^[28] Memorial Hall is located on 83 Court Street in downtown Plymouth. In his youth he had seven division championships and six coastal league championships in an accredited national soccer league. He scored goals and points at the high school Division 1 player level.

O'Neil weighed 211 pounds for the boxing match, while Preston Hartzog weighed in the vicinity of 280 pounds. Hartzog was a member of the U.S. Army World Class Athlete Program on Fort Carson at the time of being stopped. ^[1] He was 1997 and 1998 all Army superheavyweight champion. O'Neil was in the Air Force Martial Arts Program on Schriever Air Force Base.^[63]

The bout was sanctioned by USA Boxing and officially ruled as a technical knockout victory in favor of O'Neil. The owner of the 3D Boxing Gym was Dickie Wood. O'Neil trained for over one hundred days leading up to his bout with Hartzog when he was in the United Arab Emirates as part of the 763rd Expeditionary Air Refueling Squadron at Al Dhafra Air Base.^[33] O'Neil spoke about his bout with Hartzog on the Fight News Unlimited Combat Sports Show with Rich Bergeron in June 2020.^[52]

Hartzog was 1997 US Armed Forces Boxing Champion in the superheavyweight division.^[12] Hartzog won a silver medal at the Military World Games in Croatia in 1999. O'Neil belonged to the 11th Space Warning Squadron. Lockheed Martin employee Steve Griffin of O'Fallon, Illinois helped provide facilitation for the bout.^[19] U.S. Air Force Captain Heather Yates also helped in the process. O'Neil discussed his match with Hartzog on The Boxing Source in December 2020.^[53]

Preston Hartzog defeated Wesley Correira in a mixed martial arts bout at the Neal S. Blaisdell Center in Honolulu, Hawaii on November 14, 2000.^[14] Correira holds wins over Eric "Butterbean" Esch and Tank Abbott. ^[5] Correira fought in four Ultimate Fighting Championship events from 2002 to 2004.^[57] Abbott was later used as a springboard for the career of Kimbo Slice. Correira defeated Butterbean in a K-1 kickboxing match in 2008. Butterbean defeated Peter McNeeley in 1999 and went ten rounds with Larry Holmes in 2002.^[59] Hartzog went on to hold a professional boxing record of 15 wins, 1 loss, 1 draw, with 4 wins by knockout. On August 5, 2005, Hartzog competed in a six round professional boxing match against Willie Chapman and lost. The bout was held at The Orleans in Las Vegas, Nevada.

Preston Hartzog vs. James Toney was an unsanctioned boxing exhibition that occurred at the Wild Card Boxing Gym in Los Angeles on August 17, 2004. The Wild Card Boxing Gym was inducted into the National Boxing Hall of Fame in 2016. In 2003, Toney beat former WBC/WBA/IBF/lineal heavyweight world champion Evander Holyfield by technical knockout. James Toney vs. Evander Holyfield occurred at the Mandalay Bay in Las Vegas. Holyfield is one of thirty one lineal heavyweight champions in the last one hundred years. He was only stopped twice in the course of the action in his career.^[62]

He graduated from Plymouth North High School in 1994. O'Neil graduated with a B.S. from Colorado Christian University in 2001 which he applied to a salaried position with Harvard University in 2002. This was O'Neil's last boxing match. O'Neil graduated with a Master of Business Administration from Regis University in 2004. He competed for Clark County Commission in Nevada in 2006 and lost to Rory Reid. In 2017 and 2018, he did agency acquisition interviews for Northfield Leads Inc.

Preston Hartzog died in 2006.

He was a chief sparring partner to Vitali Klitschko for the Lennox Lewis vs. Vitali Klitschko WBC heavyweight world championship boxing match at the Staples Center in Los Angeles, California in June 2003. Hartzog's boxing career was covered by Eurosport.com.^[61]

Matthew E. O'Neil used the training facility in the basement of the Missile Defense Integration and Operations Center (MDIOC) for three years while in the active duty military. On July 28, 2000 he contacted United States Air Force Captain Heather Yates and Lockheed Martin defense contractor Steve Griffin to properly record the Hartzog victory to help produce the first Division 1 baseball scholarships for Plymouth, Massachusetts. Plymouth North baseball coach Dwayne Follette and former football coach Carl Freyermuth were also involved in the process.^[25]

The outcome of the bout was reported on the Internet websites maxboxing.com and newslocker.com. The bout was covered by reporter and author John J. Raspanti.^[8] Raspanti coauthored the book Intimate Warfare. The book won an award in 2017 from the West Coast Boxing Hall Of Fame. It can be found in the Chicago Public Library. Raspanti wrote Blood On My Notebook: Dispatches from the world of Professional Boxing; the book was published in 2019 and it is available on Amazon.com. Raspanti was the co-host of The Ringside Boxing Show. O"Neil gave his opinion to Everipedia in 2020:

As O'Neil prepared for a boxing comeback in 2018, Raspanti wrote "You only live once.

Just ask Matthew O'Neil".

The following is an excerpt from the article:

Matthew E. O'Neil was on an episode of The Grueling Truth in 2020 in which he spoke about his boxing match with Hartzog. O'Neil was interviewed by Mike Goodpaster and Jeremiah Preisser. Goodpaster is the former head coach of the Owensboro Rage, Evansville Rage and the Northern Kentucky River Monsters.^[54] The teams were part of the defunct Continental Indoor Football League. Preisser is a member of the Transnational Boxing Rankings Board.

O'Neil was on episodes 18 and 26 of "Split Decisions", which is an AkHi TV production.AkHi TV is based out of New York City. He was on episode 26 of the show on March 15, 2020 at the 37th minute.

YSM Sports Media did a followup on O'Neil's boxing career in April 2020. Jamil Parker asked him what got him started in boxing. O'Neil responded that he was selected based upon his run time for the 4 miles by an E-7 while serving in the Air Force in Mississippi. O'Neil also stated that he was a power hitter in baseball and softball and that he had scored 20 points in a basketball game before.

The United Kingdom based company Intuboxing covered O'Neil's career in 2020:

In May 2020, O'Neil presented his idea of a boxing comeback to the President of the New Jersey Boxing Hall of Fame. The President of the New Jersey Boxing Hall of Fame since January 1986 is Henry Hascup. Hascup is also the President of the New Jersey Diamond Gloves competition since January 1988 and is a past President of the New Jersey Association of USA Boxing. Hascup has also been a contributing editor for BoxRec.^[56] The O'Neil-Hartzog result was given to Main Street Sports Bar (Plymouth, Massachusetts) in 2021. O'Neil's biological son, Dan Marshall, resides in Ontario, Canada. Marshall's mother, Patricia Marshall, also resides in Ontario and is of partial Inuit ancestry.^[60]