Arsene Wenger

One of the greatest managers of the modern era, Arsene Wenger managed 828 premier league games, more than any other manager. A man who was responsible for the only undefeated season in Premier League history(2003–04) with his so-called his "Invincible" side, revolutionized English football with his ideas about fitness regimens and raising the levels of professionalism. He won three premier league titles and 7 FA cups with the gunners.
Wengers specialized in scouting talented, exhilarating young players from all over the planet(especially Africa and France) and grooming them into stars. Players like Thierry Henry, Robin Van Persie, and Cesc Fàbregas owe their success to the Frenchman.
Wenger made sure that Arsenal remained competitive in the league and managed a top-four league finish every single time, even during the financial crises in the second half of previous decade when the club was often forced to sell their best players to pay back the loans which were taken to build the Emirates stadium.