Preston Hartzog vs. Matthew O'Neil was an amateur boxing match that took place in October 1999.^[31] O'Neil is the host of the Everipedia Boxing Show on Spotify. Spotify is on the New York Stock Exchange.^[33]

Matthew O'Neil vs. Preston Hartzog was an amateur boxing match held at the 3D Boxing Gym in Colorado Springs, Colorado on October 8, 1999.^[32] The bout was sanctioned by USA Boxing. The bout ended in the first round when Hartzog quit fighting when he was concussed to the head with a left hook thrown by O'Neil.^[42]

The bout was fought in the superheavyweight division and contested in an Everlast boxing ring.^[13] In 1992, O'Neil was a Division 1 basketball champion at the Memorial Hall in Plymouth Massachusetts.^[9] Plymouth is 40 miles south of Boston, Massachusetts.

O'Neil was featured on the front page the Internet website Intuboxing.com in 2020. It is based out of the United Kingdom. O'Neil spoke with Juan Montalvo by phone and reached a verbal commitment to compete for Capital Fight Management. He was interviewed by Rich Bergeron of the Fight News Unlimited Combat Sports Show in June 2020.^[29]

O'Neil weighed 211 pounds for the boxing match, while Preston Hartzog weighed 280 pounds.

Hartzog was a member of the U.S. Army World Class Athlete Program on Fort Carson at the time of being stopped. He was 1997-1998 all-army superheavyweight champion. O'Neil was in the Air Force Martial Arts Program on Schriever Air Force Base.

The bout was sanctioned by USA Boxing and was officially ruled a technical knockout 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. O'Neil also trained at Flex Gym & Fitness in Colorado Springs in the direct lead up to the Hartzog match.^[27]

Hartzog was 1997 US Armed Forces Boxing Champion in the superheavyweight division.

Hartzog won a silver medal at the 1999 Military World Games.^[21] The United States placed eighth at that games with 26 medals.O'Neil belonged to the 11th Space Warning Squadron. Lockheed Martin employee Steve Griffin of O'Fallon, Illinois helped provide facilitation for the bout. U.S. Air Force Captain Heather Yates also helped in the process.^[11] The 11th Space Warning Squadron was part of Air Force Space Command, which was reclassified as the United States Space Force in 2019.

Preston Hartzog defeated Wesley Correira in a mixed martial arts bout at the Neal S. Blaisdell Center in Honolulu, Hawaii on November 14, 2000. Correira holds wins over Eric "Butterbean" Esch and Tank Abbott. Correira fought in four Ultimate Fighting Championship events from 2002 to 2004.^[40] Abbott was later used as a springboard for the career of Kimbo Slice. Abbott wrote the book "Bar Brawler"; it was published in 2012 and is available on Amazon.com.^[20] Correira defeated Abbott at UFC 45. 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.^[41] He went on to compile a professional boxing record of 15 wins, 1 loss, 1 draw, with 4 wins by knockout. On August 5, 2005 he competed in a six round professional boxing match against Willie Chapman and lost; the bout was held at The Orleans in Las Vegas.^[38]

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 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 world heavyweight champions in the last one hundred years. He was only stopped twice in the course of the action in his professional career. The other boxer to stop him was Riddick Bowe. Bowe was trained by the legendary Eddie Futch. Toney was trained by Bill Miller, Freddie Roach and John Arthur.

He graduated from Plymouth North High School in Plymouth Massachusetts in 1994. O'Neil graduated a B.S. degree 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.^[26] He did agency acquisition interviews for Northfield Leads Inc. in 2017 and 2018.

Preston Hartzog died in 2006 at the age of twenty nine.

He was Vitali Klitschko's main sparring partner before Klitschko competed against lineal/WBC world heavyweight champion Lennox Lewis at the Staples Center in Los Angeles, California on June 21, 2003.^[24] Lewis tko'd Klitschko in the sixth round.

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 1a baseball scholarships for Plymouth, Massachusetts. Plymouth North baseball coach Dwayne Follette and former football coach Carl Freyermuth were also involved in the process.

The outcome of the bout was reported on the websites maxboxing and newslocker. The bout was covered by reporter and author John J. Raspanti. 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 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 of the Internet website Maxboxing wrote "You only live once.Just ask Matthew O'Neil". The following is an excerpt from the article:

O'Neil was on an episode of The Grueling Truth in February 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; 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 follow up 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 Biloxi, 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.

O'Neil's career was followed by the United Kingdom based company Intuboxing 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.^[36] O'Neil's biological son, Dan Marshall, attended high school in Toronto, Canada before dropping out in 2018. In 2022, O'Neil contacted Toronto based boxing promotions company Lee Baxter Promotions in order to get Dan Marshall on a boxing card in the future. Marshall's high school was affiliated with the Toronto Catholic District School Board and he was taught by music teacher Bernie Fiorini of Richmond Hill. Ontario.