Largely unknown outside the tight borders of the Bundesliga just weeks ago, he has now become a household name.
Fullkrug scored a crucial 83rd minute equaliser against Spain after coming on as a substitute on Sunday to keep alive Germany's hopes of advancing to the knockout stage of the World Cup.
The Werder Bremen forward had not played a senior international match until two days before the team arrived in Qatar.
He scored on his debut against Oman, their last warm-up game before the tournament started, and now has two goals to his name from his three caps.
The burly centre forward was a last-minute inclusion, almost by popular demand, after a sensational Bundesliga season that saw him score 10 times in their 14 games so far.
With Germany long struggling with their attack, playing for eight years without a natural target man and instead choosing 'fake nines', coach Hansi Flick's decision to bring him to Qatar has already paid dividends.
He thundered in a shot from a tight angle to earn his team's first point after they had suffered a shock 2-1 opening defeat by Japan.
But Fullkrug's road to the World Cup could not have been more unusual.
A product of Werder Bremen's youth system, Fuellkrug struggled to find a place in the team and spent years with lower division clubs including Greuther Fuerth, Nuremberg and Hanover 96.
He only returned to Werder in 2019 but with the team relegated the next season he was back at plying his trade in the second division.
His recent rapid rise has drawn parallels with all-time World Cup top scorer Miroslav Klose, who in 2014, when Germany lifted their fourth world title in Brazil, was the only member of the squad not to have gone through Germany's youth system at the time.
From an apprentice carpenter to the big league, Klose showed another way to get to the top.
Fullkrug's career is similar in that he was never part of the elite of German football to earn a call-up for the senior squad. His career seemed destined to be one of an also-ran in the lower tier.
But his recent Bundesliga scoring form has now spilled over to the World Cup and 'The Gap', as he is know due to a space between his front teeth, is being hailed as Germany's improbable hero.
Polls in German are now asking whether he should be an automatic starter as the team are desperate for more efficiency in front of goal ahead of their last Group E match against Costa Rica on December 1.
Whatever the rest of the World Cup bring him, the centre forward has already secured his spot in Germany's football anthology and Flick will hope it is just the start of a warm and sunny Indian summer for his striker in Qatar.
