The boy took a liking to boxing with his first encounter, then became an energetic young fighter, winning his first 25 fights, and aggressively reaching for tougher, even older and bigger, opponents.

[3][7][13][14] At Wichita North High School, Hernandez also excelled in wrestling, eagerly taking on better and bigger opponents with a ferocity and endurance that shocked them, and his coach.

[7] Young Hernandez' amateur boxing career—with only 4 losses in over 90 fights—included, by age 21, eight wins in the Ringside World Championship (an annual Kansas City-area event billed as "the largest amateur boxing tournament in the world"[15][16]), along with six consecutive Silver Gloves National Championship wins, and a 2014 National Golden Gloves gold medal.

At the 2016 American Boxing Olympic Qualification Tournament held in Buenos Aires, Argentina, he won the silver medal in the men's flyweight.

He defeated Argentina's Leandro Blanc in the semifinals to secure his place in the Olympic competition and advanced to the final to face Yuberjen Martinez of Colombia.

[3][5][6][14][18] Ironically, Walsh had previously coached Brendan Irvine, an Irish boxer who, the year before, had defeated Hernandez in the starting round of a world championship fight in Qatar.

[3][14][18] In his second fight, low-seeded Hernandez faced Russia's Vasili Egorov, second-seeded, and silver medalist of the last world championship—the defending European champion.

An accidental head-butt gashed Hernandez, leading to a bloody face and briefly blurred vision; a doctor cleaned him up between rounds 2 and 3, but he did not rebound fully.

"[3][6] Hernandez was Wichita's first Olympic medalist since the 1984 team gold medal wins of women's basketball star Lynette Woodard and men's volleyball athlete Marc Waldie.

His first two fights in 2017, at age 21—before thousands of fans at local arenas, and nationally televised by the CBS Sports Network—both ended in knockout victories for Hernandez.

[8][25][23][5][11][12][26] Hernandez's first professional fight, on March 25, 2017 (in front of 3,100 fans at the Kansas Star Arena of the Kansas Star Casino, near Wichita, and televised nationally by CBS Sports Network), was against Las Vegas novice pro Patrick Gutierrez, a junior bantamweight fighter who had lost his two previous pro matches, and passed up a third "easy fight" to instead challenge Olympic medalist Hernandez, hoping that defeating him would gain him quick elevation to national prominence.

[11][26][23] Hernandez's second pro fight, on June 17, 2017, in front of 2,000 boxing fans just outside Wichita at Hartman Arena in Park City, was initially broadcast nationally on CBS Sports Network (until a storm knocked out communications).

Rodriguez was trained by Angel Manfredy, himself a successful lightweight boxer (43–8–1, 32 KOs) and four-time world title challenger, who'd fought Floyd Mayweather Jr., Diego Corrales and Stevie Johnston.