The Texas native was just five when his family relocated from the USA to Germany - a transatlantic twist of fate that opened his eyes to soccer, changing the course of his life forever.
"We were stationed in Fort Lee, Virginia," Weston's Dad, John, explained to ussoccer.com as part of their new series 'RISING: Emerging Faces of the U.S. Men's National Team'. "It was just coming up on time for me to make a PCS - permanent change of station - and I had an option to go to Alaska or go with Germany. I talked to the family about it and it's like, 'Ah, we don't want to go to Alaska, it's too cold there.' So we decided to go to Germany, and take advantage of the traveling and seeing things and some of those things when we ended up there."
For young Weston, one of those things was soccer. He began to play regularly - with his older brother John and friend Toby - across the road from the family home, at the village sports hall. Even then, he was a cut above the rest.
"I remember we were in there playing, a bunch of 16 to 20 year olds," said David Müller, coach of local youth team FC Phönix. "There were these two Americans, one of them 14 years old, one of them five years old. If he had the ball, you could see he was pretty good. That was Weston. I went to his brother and said, 'Why don't you bring him out to the local team I just took over? It's exactly his age group.'"Weston obliged - not that it was entirely age appropriate. He rattled off eight debut goals for the U6s, prompting Müller to bump him up not one, but two age groups. The move paid tenfold.
"As long as he was there, we didn't lose a game," Müller remembers. "I think the mentality he has now comes a lot from this time because I didn't like excuses. I always knew he'd make it."
If McKennie thought a career in soccer was pie in the sky, he soon changed his mind. After watching the USA beat Poland in a pre-2006 FIFA World Cup friendly in nearby Kaiserslautern, the Texan youngster had the good fortune to meet USMNT players Landon Donovan and Carlos Bocanegra. The touch paper was lit.
"It definitely was a life-changing experience for me because before I moved to Germany, I really didn't know soccer was a sport," McKennie said. "In football, there's no national team or anything, so I didn't know there was a national team where you can play for your country and the best kids in the country play together.
Watch: Schalke's wonderkid, Weston McKennie
"And so when I met those guys and I said, wow, I can aspire to be something even bigger than just playing for a club or just from my little village at the time. I didn't really know how you've gone about that or how you get to that moment, but I knew I kind of want to get myself there at some point."
That time would come sooner rather than later. Although the McKennies returned to Texas when Weston was a teenager, he continued to pursue his soccer dream at the FC Dallas Academy, helping them to the 2015/16 U.S. Soccer Development Academy Championship match by scoring the opening goal in a 4-0 win over the New York Red Bulls.
Professional soccer stardom was just around the corner - figuratively at least. However, instead of signing a college scholarship with the University of Virginia or a Homegrown contract with FC Dallas, McKennie plumped for a return to his soccer roots in Germany - with Schalke.
"I remember when we took a tour of the Veltins Arena," said Tina McKennie. "You could see it in his eyes. He told me, those eyes, without telling me. This is home."
Schalke's Veltins Arena, nestled in the old mining community of Gelsenkirchen, has been McKennie's adopted abode since August 2016. He made 21 appearances for the U19s in 2016/17, before getting his big break with the first team the following campaign (23 Bundesliga outings). The 19-year-old also earned his first caps for the USMNT, scoring on debut in a friendly against Portugal in November 2017.
"Coming from not playing in front of anybody to playing in front of 60,000 people [...] it's something I dreamed of for so long," McKennie admitted. "We live, eat, breathe soccer here. [The fans] bleed for the crest. They'll do anything for us. And that's something that I think they realized - that I'll do anything for them. It's a community based on hard work, and every day I prove myself a part of it."