On 27th October 2015, history was made when a 28-year-old manager took over at crisis-hit Hoffenheim who were lingering around the relegation zone in the Bundesliga. Eyebrows were raised at the appointment of the youngest manager in Bundesliga history, and his ability to steer them away from relegation was questioned by many.
However, the former Hoffenheim Under-19 coach answered his critics by guiding his club to a win in 7 of their remaining 14 games, ultimately cementing his position at the club for the foreseeable future.
Even after such a promising show in his first few games in charge, his next season at the helm still surprised many. More of an expert at team bonding and player psychology than tactical football, the baby-faced manager led Die Kraichgauer to a stunning fourth-placed finish in the 2016-17 season.
It was then that Tim Wiese labelled him "Mini Mourinho" - high praise for a young manager still at the beginning of his career.
Though a disciple of Thomas Tuchel and an outspoken admirer of Arsene Wenger, Nagelsmann draws comparisons to a plethora of other managers around the globe. But where he differs from most other managers is that for him, the tactical nuances of football matter little.
"You only see teams adhering to formations after kick off and perhaps eight times after that"
Nevertheless, his inclination towards team harmony and man management did show tremendous results in his first full season at the club.
Ups and Downs
Finishing above the likes of Schalke and Leverkusen, and just two points behind third-placed heavyweights Borussia Dortmund, he broke the stereotype of balding or grey-haired Bundesliga managers.
His exploits at the very top of German football captured hearts the world over. However what followed was an anti-climax of sorts.
Two of his most cherished players, Niklas Sule and Sébastien Rudy were prised away by Bayern Munich. However, the acquisition of social media sensation Felix Passlack (those skills with the bubblegum were neat) from Dortmund and the brilliant Serge Gnabry from Arsenal on loan showcased his ambitions for the next season.
Back home, things were going their way. A 2-2 draw against Leverkusen and a well-deserved 2-0 victory against mighty Bayern made other clubs take notice. In the UEFA Europa League, things started to go downhill yet again.
The draw was unkind to them, but their excellent performances back home meant they were favourites to top the group. However, those expectations were dashed in spectacular fashion as they collapsed against lesser-known clubs to be rooted to the bottom of the group, collecting only five points in the process.
It was when Hoffenheim was dumped out of the DFB Pokal in the second round itself that question marks were raised over Nagelsmann's future at the club. Inconsistent performances in the Bundesliga made them slip out of the top four, and it was wondered whether Nagelsmann was, after all, only a one season wonder.
Sign of Hope?
But that did not stop him from being linked with a move away to one of the big clubs. With Bundesliga heavyweights Bayern and Dortmund having managers with short-term contracts, it did not come as a surprise when Nagelsmann was linked to a job at either club.
However, the baby-faced genius decided it was better to stay on, which was perhaps a good decision. If he keeps showing his class and proving his doubters wrong, Hoffenheim might just better their remarkable performances of last season this year.