The German put pen to paper on his deal with the Reds on October 8, 2015 at a city centre hotel, beginning a fresh chapter in his career after successful managerial spells with Mainz and Borussia Dortmund in his homeland.
Klopp would take the helm for the first time nine days later – a goalless draw at Tottenham Hotspur – to start his Anfield tenure.
In total, the 52-year-old has presided over 221 matches as Liverpool boss, during which time his side registered a club-record 97 points in a single season and, of course, lifted the UEFA Champions League and Super Cup trophies.
To mark the anniversary, official LFC statistician Ged Rea has collated a range of facts and figures from Klopp’s four years as Liverpool manager…
517 - most consecutive minutes in all competitions without conceding a goal under Jürgen Klopp (February-March 2019).
458 - goals scored in all competitions under Jürgen - averaging 2.07 goals per game, the highest ratio by any Reds manager in the last 123 years.
320 - points won by Jürgen Klopp in the Premier League, from the 152 matches at an average of 2.11 per game.
221 - number of games played so far in the Klopp era in all competitions.
197 - Roberto Firmino has made most appearances for the club since Jürgen took charge.
197 - the number of games taken to manage his Liverpool team to 400 goals - faster than any other Reds boss.
146 - the number of games it took Jürgen to record 300 league points - the fewest games required by any Reds boss to reach the landmark.
92 - the number of wins recorded by Klopp in his first 150 league games in charge, more than any other Liverpool manager in history.
88 - clean sheets kept by Liverpool in all competitions since Klopp was appointed - the first coming against Tottenham in October 2015.
77 - the tally of goals scored by Liverpool's highest scorer under Klopp - Mohamed Salah.
68 - cup ties have been played by Liverpool (30 Champions League, 14 League Cup, 13 Europa League, 10 FA Cup, 1 European Super Cup) under the German.
67 - players used by the club during Klopp's 221-match tenure.
58.82 - the percentage of wins overseen by Jürgen Klopp in his four years at the helm (130 in 221 games) - a percentage bettered by only one previous manager, John McKenna (69.44).
53 - different teams Klopp has faced as Reds boss - he has beaten 50 of those.
49 - goals scored by Liverpool substitutes, with the most coming from Divock Origi (9).
44 - the average number of minutes between Liverpool goals (458 goals in 20,010 minutes).
43 - the number of occasions the Reds have scored four goals or more in a game.
39 - the number of times the most used centre-back pairing has been deployed with Joel Matip and Virgil van Dijk on the losing team only five times.
38 - the number of different Liverpool players to have scored under Klopp - Emre Can the first, Ki-Jana Hoever the latest to net for the first time.
37 - players have been given their Reds debut, with Connor Randall being the first and Sepp van den Berg the last.
22 - the winning score that the Reds have recorded most often is 2-1 (22 times).
21 - the average age of the youngest starting XI fielded by Klopp, and indeed, ever by Liverpool - against Plymouth in the FA Cup in January 2017 (21 years 296 days).
20 - the number of times Reds have come from behind to win a game in league and cup.
17 - successive league victories recorded under Jürgen Klopp (currently) - a best ever for the club.
15 - the quickest goal in seconds scored by a Liverpool player from the start of a game (Naby Keita against Huddersfield Town in April 2019).
14 - the number of different players to captain the team - Milner, Toure, Lucas, Henderson, Benteke, Allen, Enrique, Flanagan, Skrtel, Can, Coutinho, Mignolet, Lovren and Van Dijk.
14 - the number of teams Liverpool are unbeaten against in the Premier League under Jürgen Klopp.
8 - the current run of successive away league victories - the most ever by any Liverpool manager.
8 - the most consecutive victories recorded in a single calendar month by any Reds boss - December 2018.
5 - in 2019 he became the fifth German coach to win the European Cup/Champions League after Dettmar Cramer, Jupp Heynckes, Ottmar Hitzfeld and Udo Lattek.
1 - the first manager ever to take an English team to three European finals in his first three seasons of European competition.