THE FASHION at Wednesday’s inauguration put American designers front and center, including several emerging American designers—who particularly stand to benefit from the attention. President Joe Biden’s Ralph Lauren suit got respectful reviews, but outfits designed by Sergio Hudson and Alexandra O’Neill, names far less widely known, were singled out for special praise. This level of exposure can make a huge difference, said Ikram Goldman, the Chicago retailer who gravitated to the work of many undersung designers when helping style Michelle Obama during the Obama administration. “These are unknown designers that are being worn by people in the limelight,” she pointed out, “and that combination…makes an impact on a lot of levels.”

Chief among them, sales. Batsheva Hay, who designed the high-necked burgundy dress worn by Ella Emhoff—the stepdaughter of Vice President Kamala Harris—said her e-commerce transactions started reaching record highs after the inauguration: “Compared to a regular day, I did at least five times as many sales on my website.” Ms. Hay is seeing unprecedented levels of interest manifest in other ways, too. A photo she posted on Instagram of Ms. Emhoff in her dress garnered more than 12,000 likes, thousands more than her typical posts.

Online interest also spiked for the family team behind the ornate, bird-adorned ring worn by poet Amanda Gorman. “We had the most people we’ve ever had on our website yesterday,” said Octavia Giovannini-Torelli, who runs the jewelry line Of Rare Origin with her mother and sister. “We’re responding to every single client who has reached out.” Since Wednesday, their website has featured a banner that reads: “We’re honored (and freaking out) to have a birds-eye-view at this historic Inauguration.”

Sergio Hudson, the Los Angeles-based designer who created the plum outfit that Michelle Obama wore at Wednesday’s inauguration and the black cocktail dress that Vice President Harris wore that evening, said his Instagram following multiplied from around 50,000 to over 130,000 in the hours following the inauguration. He says he’s barely had a chance to check sales and web traffic between all the interviews that have resulted.

The increased attention is especially welcome after a year that, thanks to the pandemic’s impact, ranks as one of the fashion business’s worst. “It means validity in the industry at a time where I feel like the industry is struggling,” Mr. Hudson said. “The past year has been scary. You’ve wanted to be a designer your entire life and then in one year you’re like, watching the whole industry collapse….This shows people still believe in fashion.”