Ever since a child first set foot on a stage, there have been showbiz parents. The same goes for kids’ athletic endeavors and sports parents. They’re the ones urging the director or coach to give their son/daughter bigger roles, more opportunities, better parts, etc. Some of them become abusive whiners when they feel their offspring isn’t being used to their maximum potential, whether it’s on a soccer field or a high school drama production of “Hairspray.”

At first glance, Richard Williams would seem to be yet another of those dads, unwilling to accept anyone else’s advice on how his tennis-playing daughters, Venus and Serena, should practice or play matches or use an open stance when returning balls. But in Richard’s case, he had a plan designed to turn his girls into tennis phenoms.

As we all know, his strategy worked, producing two of the most remarkable tennis players of all time. But it took quite a bit of pushing back against a racist system and a patronizing social structure that looked down its nose at these girls from Compton and their brash father.

That’s the way “King Richard” frames the Williams sisters’ success, and it does so in stunning fashion, led by Will Smith’s performance as the title character. As he did in his Oscar-nominated portrayal of Muhammad Ali, he becomes so embedded in the role that it took me only about five minutes to forget I was watching Smith. It’s one of the best things I’ve ever seen him do, brilliantly capturing Richard’s stubborn smarts at full boil, while still allowing some glimpses of the troubled man simmering within.

But the movie doesn’t belong entirely to him. Saniyya Sidney is remarkable as Venus, the older sister, and thus the first to get a bite at the tennis apple. Sidney not only handles the dramatic scenes well, but pulls off completely believable tennis-playing sequences that don’t look to me as if they’re CGI-enhanced. Even more amazing is that Sidney is a natural left-hander who had to learn to play high-level tennis right-handed to emulate Venus.

She’s ably supported by Demi Singleton as Serena, who Richard insisted be taught all the same methods and given similar opportunities, and the two actresses give the siblings a nice, warm chemistry that’s shared with their older sisters, too. Aunjanue Ellis deserves acclaim as the girls’ mother, Oracene, who had to support her daughters, teach them some of her own skills, and not get bulldozed by Richard. There’s a particularly moving scene in which Oracene stands up to him to ensure he knows he’s not solely responsible for Venus and Serena’s achievements.

“King Richard” could easily have fallen into the trap of so many other sports movies by focusing on the Wiliams sisters’ professional success as adults. In the hands of writer Zach Baylin and director Reinaldo Marcus Green, it avoids most of those cliches by focusing on the developmental years, in which Richard did unorthodox things like withdrawing 11-year-old Venus from competitive matches for three years because he didn’t want her to burn out as Jennifer Capriati and Tracy Austin did in their teens. There’s also a great sequence in which Venus’ coach, Rick Macci (a very good Jon Bernthal) can’t believe his ears when Richard and Venus turn down a three-million dollar endorsement deal, knowing bigger offers would come.

The movie doesn’t pay much attention to Richard’s dark side, which is to be expected in a biopic that was produced by his daughters with full Williams family approval. But there’s still enough compelling story to tell, and “King Richard” does it in winning style. Even non-tennis fans will get a kick out of this movie, which will be among the titles on my Best Of 2021 list next month.

I give “King Richard” a 9 out of 10. Opens today in theaters and streaming on HBO Max.