Mays, 50, was found unresponsive by his wife inside his Tampa, Fla., home at 7:45 a.m. on Sunday, according to the Tampa Police Department.
Police said there were no signs of forced entry to Mays' residence and foul play is not suspected. Authorities said an autopsy should be complete by Monday afternoon.
"Although Billy lived a public life, we don't anticipate making any public statements over the next couple of days. Our family asks that you respect our privacy during these difficult times," Mays wife, Deborah, said in a statement on Sunday.
Mays was well known for his numerous television promotions of such products as Orange Glo and OxiClean. He was also featured on the reality TV show "Pitchmen" on the Discovery Channel, which followed Mays and Anthony Sullivan in their marketing jobs.
Born William Mays in McKees Rocks, Pa., on July 20, 1958, Mays developed his style demonstrating knives, mops and other "as seen on TV" gadgets on Atlantic City's boardwalk. For years he worked as a hired gun on the state fair and home show circuits, attracting crowds with his booming voice and genial manner.
After meeting Orange Glo International founder Max Appel at a home show in Pittsburgh in the mid-1990s, Mays was recruited to demonstrate the environmentally friendly line of cleaning products on the St. Petersburg-based Home Shopping Network.
Commercials and informercials followed, anchored by the high-energy Mays showing how it's done while tossing out kitschy phrases like, "Long live your laundry!"
Recently he's been seen on commercials for a wide variety of products and is featured on the reality TV show "Pitchmen" on the Discovery Channel, which follows Mays and Anthony Sullivan in their marketing jobs. He's also been seen in ESPN ads.
His ubiquitousness and thumbs-up, in-your-face pitches won Mays plenty of fans. People line up at his personal appearances for autographed color glossies, and strangers stop him in airports to chat about the products.
"I enjoy what I do," Mays told The Associated Press in a 2002 interview. "I think it shows."
Mays was on board a US Airways flight that blew out its front tires as it landed at a Tampa airport on Saturday, MyFOXTampa.com reported.
US Airways spokesman Jim Olson said that none of the 138 passengers and five crew members were injured in the incident, but several passengers reported having bumps and bruises, according to the station.
Authorities have not said whether Mays' death was related to the incident.
Discovery Channel spokeswoman Elizabeth Hillman released a statement Sunday extending sympathy to the Mays family.
"Everyone that knows him was aware of his larger-than-life personality, generosity and warmth," Hillman's statement said. "Billy was a pioneer in his field and helped many people fulfill their dreams. He will be greatly missed as a loyal and compassionate friend."