Fila re-released a 1990s sneaker and revived a dying brand.

Fila had spent more than a decade fading: the sportswear brand lost its U.S. position, and by the mid-2010s it was a name mostly remembered from childhood. Its Korean parent, Fila Holdings, needed something to make the brand matter again.

The answer was the archive. In 2017 Fila re-released the Disruptor 2, a chunky-soled sneaker from the 1990s, just as millennials made 'dad shoes' a fashion category. The Disruptor became one of the most popular women's shoes of 2018, Bloomberg reported.

The numbers followed: Fila's footwear and apparel sales, excluding its golf business Acushnet, rose 52% to 1.2 trillion won in 2018, and U.S. sales grew 21% in the second quarter of that year, contributing to record earnings.

Investors noticed. Fila's shares rose about 400% from the start of 2018 through mid-2019, pushing the company's market value to $4.3 billion, and the executive who bet on the relaunch saw his stake become worth roughly $830 million.

Fila's footwear and apparel sales rose 52% to 1.2 trillion won in 2018; U.S. sales grew 21% in Q2 2018; shares climbed 400% to a $4.3B market value.

The Disruptor was authentic heritage — real 1990s DNA, not a fake throwback.

It hit the dad-shoe trend at the exact moment the trend peaked.

An accessible price and wide distribution kept it everywhere young shoppers were.

Retro sneakers are inherently photogenic, so the product did the marketing.

A dormant brand can ride a trend with a hero product from its own archive: relaunch the icon at the right price, and the past becomes the fastest new thing you own.

Fila rode the chunky-sneaker wave through 2019, and the revival became a case study in using a heritage product to reconnect with a new generation.