Sometimes first impressions can be a little misleading but more often than not they’re usually spot on. That was certainly the case when German football was properly introduced to Ralf Rangnick in December, 1998.

After winning promotion from the third tier of German football with minnows UIm, the young and unknown head coach guided his second division newcomers to just one defeat in their first 18 games leaving them in pole position to advance to the Bundesliga.

To little surprise, German football quickly took notice of this phenomenon.

Analysts at national newspapers purred at Ulm’s style of play, describing it as a “triumph of the system” while the team were heralded to such an extent it was reported they “play like world champions”. So it wasn’t long before Rangnick was pulled onto ZDF’s Sportstudio show – Germany’s equivalent of Match of the Day – to explain his miracles.

Once there, Rangnick, dressed all in black with his unassuming haircut and glasses to boot, stood before a rudimentary tactics board and quite literally lectured for four minutes straight on the importance of a back four and having the entire team press the ball. This revolutionary outlook was delivered to a nation still insistent on watching sweepers and man marking across the pitch.

The only break in silence came from some awkward chuckles when the coach accidentally knocked the ‘ball’ off his board.

Rangnick hasn’t changed much since then. He still gives little thought to his dress sense and loves nothing more than to give monologues on football tactics and systems. But while this “football professor” has remained still, the world of football has since bent to his will and is now dominated by his theories and practices.

Following his success at Ulm, Rangnick moved to Stuttgart for his first major job where he personally hired a young Thomas Tuchel to coach the youth teams. He lasted two years at the club before turning over too many stones and floating perilously close to relegation during his second season.

Similar fates awaited Rangnick in his next two jobs. He won promotion to the Bundesliga with Hannover – where he gave a young Per Mertesacker his senior debut – before moving on to Schalke to clinch second in the German top-flight. But on both occasions the constantly tinkering and highly ambitious coach found himself butting heads with his superiors and was quickly shown the exit.

To truly showcase his talents as a visionary, Rangnick would have to once again drop down to the third tier of German football, when he agreed to take over at Hoffenheim in 2006. The village club owned by software engineer and billionaire Dietmar Hopp gave the tactician the money and the platform to build his own club from the ground up. Which is exactly what Rangnick did.

After back-to-back promotions, Rangnick’s Hoffenheim took the Bundesliga by storm by coupling his new-age gegenpressing tactics – the concept of a high press and counter attacks at every opportunity – with smart recruitment, which saw the club target young players with plenty of potential. In only their fifth game of the season, Hoffenheim blew Dortmund away with a 4-1 victory. “That’s the kind of football we want to play one day,” said a young Jurgen Klopp after the game, four years before his own take on Rangnick’s tactics would take Dortmund to the Champions League final.

In what has since become common practice at Germany’s biggest clubs, Rangnick’s Hoffenheim hoovered up young talent and played an intense style of play that saw them to challenge and out-think more established clubs on and off the pitch. “What we did in Hoffenheim had a lot of influence on German football,” recalled Rangnick in an interview with ESPN last year, before bringing up that Dortmund game. “It could easily have been six or seven.”

However, even Hoffenheim couldn’t entirely meet Rangnick’s demands and after two impressive mid-table finishes with the provincial club, the German head coach resigned after the club agreed to sell Luiz Gustavo to Bayern against his wishes in the January window.

During a brief eight-month return to Schalke, Rangnick won his first major trophy by beating Duisburg in the German Cup final but his second spell ended in resignation with him citing exhaustion. The godfather of gegenpressing was eventually enticed to the Red Bull group tasked with rebuilding Salzburg and Leipzig with the blueprint impressively devised at Hoffenheim.