But he is also arguably one of the most successful coaches as well. The German will this month celebrate his fifth anniversary coaching the U.S. Men's National Soccer Team as statistically the best it has ever had -- with 52 victories and 14 draws in 90 games since he took charge on July 29, 2011.
That 56.7% winning record might only just slightly eclipse those of his recent predecessors but, as global connoisseurs of the game are well aware, it is all the more impressive considering Klinsmann has deliberately scheduled as many risk-filled exhibition games as possible against the world's best teams -- in order to get his players conditioned for a run towards a World Cup semifinal or final one day.
After helping set Germany on an incredibly successful path of reaching at least the semifinals of the last seven tournaments it has played since 2005, with reforms he implemented as national coach from 2004-06, Klinsmann has also helped the USMNT punch above its weight in its last two major tournaments.
Last month the U.S. reached the semifinals of the 16-team Copa America on home soil, beating Costa Rica, Paraguay and Ecuador before losing to Lionel Messi's Argentina.
At the 2014 World Cup, the USMNT advanced from the so-called "Group of Death" with a win against Ghana, a draw with Cristiano Ronaldo's Portugal and a 1-0 defeat by eventual champion Germany, before -- in the last 16 -- losing in extra time to a Belgium team that has since topped FIFA's rankings. It was a noteworthy achievement in a tournament where traditional heavyweights such as Spain, Italy and England failed to reach the knockout stage.
So it should be no surprise that Klinsmann, who manages to bring out the best of his teams when it counts most in big tournaments, is reportedly on the list of candidates to become England's next manager. His uncanny ability to rise to the occasion -- and help those around him to peak at the right moment -- of World Cups, Euros and Copa Americas as both a player for Germany in the late 1980s to late '90s and coach since 2004 has not gone unnoticed.
Would Klinsmann take the England job if it were offered to him? He loved his time there as a player at Tottenham Hotspur and said he could see himself going back some day. He would be a great fit and would probably jump at the chance.
However, Klinsmann is signed up to lead the USMNT to the 2018 World Cup and, as someone who has never broken a contract before, it's unlikely he'd do it now. As he explained to me in a series of interviews for my new book "Soccer Without Borders,"
Klinsmann loves the challenges of helping to take soccer to the next level in the United States.
He's fallen in love with the country since moving to California in 1998 after retiring as a player who won a World Cup in 1990 as a West Germany player and a European championship in 1996 as unified Germany's captain. And he would love to take his team to the semifinals in Russia.
"We all want a brighter future for the U.S. Men's National Team, and we want the United States to become established as one of the world's top-10 teams," Klinsmann said. "But it's not going to be easy considering how many strong soccer nations there are around the world.
"We set an ambitious goal for the 2018 World Cup -- to reach the semifinals. And, if we start with the end goal in mind, we obviously want to win the World Cup one day. There are huge challenges, and it will take a lot of hard work. But things are definitely moving in the right direction. Our goals are challenging but achievable."
Klinsmann, 51, is pleased the game has become established in the U.S. in the last few years despite some setbacks in friendlies that led to sharp media criticism.
"Soccer has clearly made it in the United States," he said. "It's mainstream. It's recognized as a major sport. People like it. And it's growing.
"The next step is to become one of the best soccer nations in the world. The USMNT has become an important engine for growth in the United States. We're trying to do everything we can to make the national team as successful as possible in the World Cup, which is the benchmark for everyone around the world.
"The attention that soccer in the United States gets at the World Cup is what pushes the game forward for the next four years. And because we made it out of the 'Group of Death' in Brazil, the game got another big boost emotionally -- from millions of American soccer fans and from the media."
Klinsmann is sometimes misunderstood in the United States, in part because he speaks directly. He doesn't mince his words when explaining his team has a lot of work ahead of it.
"A lot of things have gone well these past years, but a lot of things need to get better," he said. "It's a long-term process and there's no room for complacency. We're working on becoming a more proactive team; we're working on developing a style in which Americans recognize themselves.
"Over time, we want to develop a belief that, 'If I'm really prepared, if I'm physically and mentally at the top of my abilities, then I'm actually able to compete with the best in the world.' We want to develop that mindset that, yes, we can do it."
Klinsmann believes the USMNT can only be successful in the long run if its foundation -- the youth system -- keeps improving and developing. It needs a soccer pyramid like other nations have, but it will take time to develop -- though he realizes Americans are impatient and want quick results.
"The foundation in the United States is still fragile and disconnected compared to other countries," he said. "The youth leagues do their own thing, the professional system is not really connected to the amateur system, and that's not really connected to the college system.
"So there are holes in the system, like in a Swiss cheese, and there's a loss of quality. We're working on connecting those pieces, on connecting player development, and on continuing to build a pyramid in this amazing country."
Above all, Klinsmann believes Americans must play more soccer at all levels to close the gap to the world's best teams.
"The more you play, the better you'll get. If you kick a ball against a house wall or against the garage for hours on end, you'll get better. It's as simple as that," he said.
"At the end of the day, the big question is: What is it that gets kids outside to play soccer for so many hours every day? What gives them that drive to do what's needed to make themselves better, every day, all year round?"
Klinsmann talks often about self-motivation and how he wishes American players could do more on their own to improve their games -- something he senses is in abundance when it comes to basketball, with widespread hunger for success in the game. That inner drive, he says, is the key to success for top soccer players everywhere in the world.
"There are a lot of fundamental questions that we still have to talk about more," he said.
"How much drive is there? How many hours a day, or how many hours each week, are the kids playing soccer? What drives them at the end of the day to make themselves better? Are the coaches properly trained and educated? Yes, the game is growing, millions of kids are playing it, but I sometimes fear a lot of that doesn't make it through the channels of communication, or it gets lost in things like the pay-per-play model in the youth sector.
"There are so many things that aren't yet connected the way they should be connected. America is such a huge, fascinating place. I think it's going to take years to get it all right."
Klinsmann is hopeful the U.S. will one day produce a superstar like Lionel Messi, Cristiano Ronaldo, Gareth Bale, Bastian Schweinsteiger or Wayne Rooney. But it will require kids committed to not only spending a few hours a week with their teams, but also two or three times that honing their skills at home.
"The one common denominator you see with all the top players is a mindset of total determination they had as youth players and kept that right up to their national team careers," he said.
"They were absolutely driven to become the best players at every level along the way, and were never satisfied. I'm not sure if the United States has developed that mindset yet. I'm not sure why it seems that some Americans with talent sometimes reach a certain level in soccer and then settle with that instead of pushing themselves to the next level.
"You need talent but also to be extremely hungry and driven -- driven by the people around you who keep pushing you -- and it doesn't help to be surrounded by people who compliment you every day and give you pats on the back."
Klinsmann believes top American players should stay as long as possible in leading European leagues rather than return home to Major League Soccer, which he says is lucrative but not helpful in terms of career development.
"When players at that level come back to the MLS, it's understandable, but it's not challenging for them," he said. "I can't blame someone coming back to make four times as much money, but for the talent they have, it's just not challenging enough. They're not playing at the highest possible level."
Klinsmann's 17 years playing in four top European leagues taught him that learning to handle the pressure and criticism in countries where soccer is treated as a 24/7 way of life is essential to succeeding on the biggest stage of all -- the World Cup.
"Our players who go to England, Germany, Spain, or France get used to the pressure and are used to getting criticized if they have a bad game," he said. "They hear about it from the local people in the supermarket or in the shops or on the streets. The pressure is everywhere. They're used to having to justify themselves for their performances all the time. Players at the professional level in MLS are not getting bothered at the supermarket the next day because they lost a game."
Klinsmann draws a parallel with the world's top basketballers, who flock to the NBA rather than stay in lesser European leagues.
"You've got to go where the world's best players are -- it's as simple as that," he said. "If you try to make that step, you throw yourself into the shark tank, and it's gonna get nasty. And you gotta fight your way through it. But ultimately it's gonna make you stronger.
"It takes that kind of mindset that will make a difference in a big tournament. When players are in a highly competitive peer-pressure environment for 11 months a year, they are far better prepared for that huge level of expectations when it comes down to a World Cup -- which is the ultimate benchmark for everyone.
"So that's why I'm saying if you can play against Manchester United on the weekend, or against Inter Milan or Bayern Munich, you'll be better prepared for that moment when you face all these top players in a World Cup. If you've never had any experience playing against Ronaldo or Messi, and suddenly see players like that lining up against you in a World Cup game, you might be a little bit intimidated. It's only natural. I would be too."
Despite the challenges and criticism, Klinsmann says he is enjoying his job.
"It's a bigger puzzle in the United States than in other countries, and it's not perfect yet. That's what makes it so exciting; we're building something great here," he said.
"We don't have a system in place like France or Germany or even South American countries. If you look at the FA in England, it's more than 100 years old and they already have their infrastructure, scouting, coaches' education, national training center, and the pyramid is connected. There's relatively little infrastructure work to do in England because it's all there.
"Here in the United States, building that infrastructure is still important. That's what's so fascinating and rewarding about this."
Klinsmann believes he is making progress with the USMNT, with historic wins in exhibition games in Mexico, Italy, Bosnia and Herzegovina, the Czech Republic, the Netherlands and Germany -- outside its usual CONCACAF region.
"The transition is happening step by step," he said. "We're playing against the bigger nations, we're attacking those bigger nations and holding our own against them. But there's no gain without pain. There's no growth without taking risks. And there's no growth without failure along the way. We're getting out of our comfort zone, and we're making some big strides forward.
"People interested in soccer both inside and outside the United States can all feel that there is so much potential for soccer here. There's a lot of work ahead of us, but we're moving in the right direction, and that's exciting."