Almost eight years later, the charismatic German has not only ended the club's league title drought, but he's also won the Champions League, FA Cup, and League Cup.
A large part of the Merseyside club's recent success has been down to Klopp's shrewd transfer dealings, although his first three signings left a lot to be desired.
Klopp's October appointment meant he had to, for the most part, work with what he had during the 2015/16 season. Especially, as January signings Marko Grujic, Kamil Grabara, and Steven Caulker failed to make an impact.
Now the end of another Premier League season means the departure of two Liverpool fan favourites as James Milner and Robert Firmino will leave the club at the end of their current contracts.
Although both men arrived slightly before Klopp, he can take credit for getting the very best out of them during their many years of service.
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Intent on replacing two key squad players, Klopp is already working away in the transfer market and Liverpool have announced the arrival of Alexis Mac Allister.
The World Cup winner is highly regarded and seems destined for great things under Klopp who will want to add another great singing to his already impressive list.
But who are the best signings at Liverpool under the German?
Here, talkSPORT.com looks at the top five, starting with a man whose transfer raised some eyebrows.
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5. Andy Robertson
While big-money signings like Mane and Salah came with huge expectations, Liverpool fans didn't know what they were going to get when Klopp snapped up a left-back from recently relegated Hull City.
Robertson didn't seem like the player who was going to fix Liverpool's leaky backline, which shipped 80 goals in the previous season, but for £10million the 23-year-old was worth a punt.
Fast forward six years and the Scotland captain has helped Liverpool win every trophy available and provided 54 Premier League assists - the most from any full-back ever - during his time at Anfield.
As Klopp looks to bounce back from a poor 2022/23 season that saw his side miss out on Champions League football, he'll surely be relying on Robertson who has ended up being the steal of the century.
4. Alisson Becker
The Brazilian completed Klopp's new-look backline in July 2018.
Lloris Karius's luckless time on Merseyside had some fans questioning the manager when it came to picking goalkeepers, but Alisson's £65m signing from Roma was greeted with glee.
Countless saves later, the Brazilian is widely regarded as one of the best shot-stoppers in football and is certainly one of the greatest 'keepers to ever grace Anfield.
Alisson even chipped in with a dramatic late goal to help Liverpool beat West Brom and ultimately secure a top-four place during the side's injury-plagued 2020/21 season.
3. Sadio Mane
Klopp's first major signing was Sadio Mane who impressed by scoring 21 goals in 67 Premier League appearances for Southampton but seemed expensive at £36m.
The 55-year-old had been tracking Mane since 2012 and finally got his man in June 2016 before he went on to score 120 goals and provide 38 assists during his 269 club appearances.
However, things could have been so different as the Liverpool legend actually came extremely close to signing for Manchester United before Klopp talked him out of it.
"I have to say, I was really close to going to Manchester United," Mane told The Telegraph in 2022. "I had the contract there, I had it all agreed. It was all ready, but instead, I thought: 'No, I want to go to Liverpool'. I was convinced to go with Klopp's project."
2. Virgil van Dijk
While Robertson is proof you don't need to spend big money to get great players, Virgil Van Dijk's signing shows that sometimes it's necessary to splash the cash.
In 2018, Liverpool fans got the greatest New Year's Day gift imaginable when it was announced Van Dijk was joining in a £75m deal that remains the most expensive the club has ever made.
Naturally, rival fans poked fun at the crazy amount of money Klopp had spent on a defender who didn't enjoy his best period of football before leaving Southampton.
However, he quickly became the best centre-back in the league and helped turn Liverpool from nearly men to a side that matched Manchester City for several years and won every trophy available.
1. Mohamed Salah
Mohamed Salah joined Liverpool in June 2017 and quickly became one of football's greatest stars which he remains today after scoring 186 times in a red shirt.
At the time, some questioned Klopp's decision to splash £44m on a player who 'flopped' during his time at Chelsea, but he quickly silenced the critics with 44 goals in his first season.
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Today, Salah is a Liverpool legend and is tied to the club until the summer of 2025 after signing a bumper new deal reportedly worth £350,000 per week.
'The Egyptian King' scored 30 goals this season as his side struggled and he will be vital to ensuring Klopp's men have a much better 2023/24 campaign.