He has no system.
Yup, none. A lot of coaches like to run the same schemes every year. Phil Jackson is famous for the triangle offense. Tom Thibodeau is the master of the strong-side box defense. Mike D'Antoni is synonymous with his seven-seconds-or-less system. But Popovich? Nothing comes to mind.
And there's a reason for this. Rather than fitting his players into his system, he designs a system around his players. The way the Spurs play now has almost nothing in common with how they played when Popovich started coaching 18 years ago. However, what has remained consistent is his approach.
Popovich does four things extremely well.
- Develop his players.
- Choose the best strategies for his players.
- Choose the best tactics for the situation.
- Get his players to execute his strategy and tactics.
During Popovich's tenure, the Spurs have been unmatched in their ability to develop their players. The team has won four championships without any major free agent signings or lottery draft picks since they took Tim Duncan first overall in 1997 . Their talent is almost entirely homegrown. Here are some of the organization's highlights:
- Helping a highly-touted top pick become the greatest power forward of all-time (Duncan).
- Turning a pair of talented but raw foreigners into All-Star level guards (Tony Parker, Manu Ginobili).
- Developing numerous young players into impactful starters (e.g. Stephen Jackson, Tiago Splitter, Kawhi Leonard)
- Turning no-names and castoffs into contributors (e.g. Malik Rose, Bruce Bowen, Gary Neal, Danny Green)
- Extending the careers of veterans chasing a ring (e.g. Brent Barry, Michael Finley, Boris Diaw)
If you're willing to put in the work, Popovich and the Spurs' staff will mold you into a quality NBA player.
Having good players is half the battle, but Popovich's excellence doesn't stop there. Once he's built an impressive roster, he creates offensive and defensive systems that maximize his players' strengths. Popovich's ability to put his players in the situations they thrive in lets him get the most out of the talent he has.
For example, consider the evolution of the Spurs' offense. For over a decade, San Antonio ran a lot of plays that looked like this one from the 1999 NBA Finals.
Here's the exact same play nine years later (even called with the same hand signal).
Popovich stuck with plays like this because they provided simple and effective ways to get his best player the ball in a great spot on the court.
Four years ago, Popovich observed that his superstar was aging and a new style of NBA defense had emerged. He realized he needed to redesign his offensive schemes to adapt to the changing landscape . Teams were making it harder to score in isolation situations, especially in the post. The pick-and-roll became his weapon of choice, and Popovich's new system turned Tony Parker into one of the most dangerous guards in the NBA. The new Spurs offense looks more like this:
Gone are the slow-moving clear-outs of old. Now the Spurs' offense features constant movement both on and away from the ball. Parker seems to be in an endless pick-and-roll with big men like Duncan and Boris Diaw. Wing shooters like Danny Green and Kawhi Leonard dart to open spots as soon as the defense gives them space. It looks like basketball ballet, but is actually grounded in cold, hard analytics. The Spurs new offense is engineered to create lots of high-efficiency layups and corner three-pointers. When everyone is in sync, the results are usually devastating.
"If you know the enemy and know yourself, you need not fear the results of a hundred battles." --Sun Tzu
As good of a strategist as Popovich is, I think he's an even better tactician. He's the master of understanding what the opponent wants to do and how to prevent them from doing it. If a team has a weakness, he will exploit it, even if doing so runs counter to the Spurs' typical style of play.
A great example of this came during last season's Western Conference Finals against the Memphis Grizzlies. Memphis' offense featured Marc Gasol and Zach Randolph, a pair of big, skilled post players. However, the Grizzlies suffered from a major lack of three-point shooting to complement their strength inside. Every team knew this, but no one was able to capitalize on it as well as Popovich's squad.
Throughout the series, the Spurs dropped their wings as close to the paint as they could and committed themselves to swarming anyone who tried to attack the basket. They left the Grizzlies' wings open and dared them to shoot from outside. This tactic worked like a charm. The Grizzlies scored just 96.8 points per 100 possessions--so bad that it would have ranked dead last in the league by over 3 points during the regular season. The Spurs swept the Grizzlies and advanced to the NBA Finals
The last component of Popovich's success is how precisely he gets his team to execute his schemes. It doesn't matter if the Spurs are running a play they've used for the past decade or one Popovich drew up during the previous timeout--you can bet on them to execute it to perfection. For all of the strategic and tactical decisions that go into basketball, the most important skill for a coach is the ability to motivate, direct, and communicate with his players. Even in a league filled with some of the best in the world at this, Popovich stands out. More than anything else I've written about, that's what makes him so good.
 They've had just two top-20 picks--Kawhi Leonard at 15 and James Anderson at 20.
 You can read more about the new style of defense in Alex Suchman's answer to What makes Coach Tom Thibodeau's defense so good?