The ad finds Atlanta Braves pitchers and future Hall of Fame members Greg Maddux and Tom Glavine at a St. Louis Cardinals batting practice, for some reason, gazing resentfully at Cardinals slugger Mark McGwire as he blasts pitches into the upper deck and delights onlookers including Heather Locklear.
At the time, Mr. McGwire was the biggest baseball player in America, locked in a race with Chicago Cubs slugger Sammy Sosa to break Roger Maris's long-standing home run record of 61.
That competition was a boon for Major League Baseball, which picked up some of the highest TV ratings it had seen in years. Over the course of that season, McGwire would appear on the cover of magazines from Time to Newsweek to Sports Illustrated.
It was enough adulation to make pitchers, even top-flight ones like Mr. Glavine and Mr. Maddux, seem like an afterthought -- a notion the Nike spot captured with comedic finesse.
"Hey!" Maddux shouts at the crowd of McGwire gawkers. "We got Cy Young Award winners here!"
At montage's end, their swings have improved enough to attract the attention of Ms. Locklear.
"Hi Tom," she smiles.
"Chicks dig the long ball," Maddux concludes.
Though it was built around baseball players, "Chicks Dig the Long Ball" was technically a campaign for Nike cross-training. The spot's art director, Jeff Labbe (who actually played baseball against Mark McGwire in high school) and copywriter, Canice Neary, originally came up with the idea for Nike Baseball.
But Creative Director Hal Curtis quickly decided "Chicks" needed to go big, and cross-trainers, which had been a high priority for Nike since the hit "Bo Knows" campaign in 1989, offered a bigger platform.
Even though the ad wasn't technically advertising baseball products, its success raised Nike baseball's profile.
"Usually, baseball was sort of a small category within Nike," Mr. Labbe said. "But then that blew it up."
The spot aired during an era when Nike's spending on TV and radio advertising was mushrooming, growing from $99 million in 1996 to more than $177 million in 1998.
It did so well that Nike asked for some follow-up spots. The results, commentaries from athletes and celebrities ranging from Gene Simmons to Heidi Klum, all riffed on the phrase "Chicks dig the long ball."
"Face it: A low E.R.A. just isn't sexy," a very sultry Ms. Klum said.
By then, the phrase had become a national phenomenon, and today, "Chicks dig the long ball" has become part of baseball vernacular. Announcers sometimes say it after calling home runs, and the original spot still makes the rounds on social media; Rays pitcher David Price tweeted it out as recently as last week.
But because the ad features Mr. McGwire, whose use of performance-enhancing drugs ruined his reputation and tainted his accomplishments in 1998, "Chicks Dig the Long Ball" still reminds some of what baseball fans now refer to as the Steroids Era.
"That ad's become an emblem," said Emma Span, a reporter and editor who covers baseball for Sports Illustrated.
The spot's enduring popularity is also a kind of proof, Ms. Span said, that baseball's fans have moved on from the steroid scandal that ultimately tarred the 1998 home-run race. On Tuesday, Nelson Cruz, who was suspended 50 games for violating MLB drug policy last August, started at designated hitter for the American League team in the All Star Game after being voted in by fans.
Mr. Labbe and Mr. Neary both went on to do plenty of other great work in sports. Mr. Labbe, now a director with Academy Films, would later write the World Series campaign "Beware of things made in October" for Fox Sports via TBWA/Chiat/Day San Francisco, and Mr. Neary, an executive creative director at Laughlin Constable, put together "What drives you?" for Gatorade.
They have some great memories, including, in Mr. Labbe's case, a "very well-signed baseball collection." But every time Mr. Labbe hears that phrase when he's watching a game, he thinks of something that's missing.
"I wish Canice and I had gotten a royalty!" he laughed.