Bob Perry was a Republican money man who funded Swift Boat Veterans for Truth, a group responsible for one of the most notorious attack ads in presidential campaign history.

Mr. Perry, who died at age 80 on Saturday night at his home outside Houston, gave about $4.5 million to pay for ads questioning John Kerry's military record during the 2004 presidential election campaign. Mr. Kerry was awarded a silver and a bronze star for heroism while an officer in charge of a swift boat in Vietnam in 1968 and 1969.

A prominent Houston home builder, Mr. Perry was no newcomer to political giving. In 2002, he helped bankroll the Republican takeover of the Texas House of Representatives for the first time since Reconstruction.

"His contribution to a cause was considered a gold standard and signal for other wealthy donors to come aboard," said Bill Miller, an Austin, Texas., lobbyist who worked with Mr. Perry since the early 1980s. "It was as close to the Good Housekeeping Seal of Approval as you could get."

A Dec. 10, 2002 photo of Houston home-builder Bob Perry, posing at the sales center at one of his Houston developments. Associated Press

Mr. Perry was also a prominent donor in the presidential elections of 2008 and 2012, when he helped finance the primary bid by Texas Gov. Rick Perry until the governor flubbed a debate and later withdrew. The two men were not related.

Mr. Perry then switched his support to Mitt Romney and was one of the three top individual donors in the 2012 election, giving a total of $23.5 million to Republican-leaning super PACS.

He had previously been a top donor in Gov. Perry's gubernatorial bids. Mr. Perry also occasionally wrote checks to Democrats who supported his position on protecting home builders from lawsuits.

John O'Neill, a Houston lawyer who co-founded Swift Boat Veterans for Truth, said that Mr. Perry's activism had its roots in the Carter administration of the 1970s.

"He just reached the conclusion that if he didn't do something, the country would go to pieces," Mr. O'Neill said.

A graduate of Baylor University, Mr. Perry taught high school before founding Perry Homes in 1967. The closely held company had grown by 2011 into the nation's eighth-largest home builder, according to Builder Online, a trade publication. In 2012, the company had $485 million in revenue. It has sold more than 45,000 homes since its inception.

Friends described Mr. Perry as a prudent businessman who was cautious with his company's finances and who was involved in the day-to-day operations of the company until the day he died.

Despite his prominence among conservative givers, Mr. Perry was seldom seen at public events or fundraisers with candidates.

But he didn't always mind drawing attention. In 2004, picketers gathered outside his home in Clear Lake, southeast of Houston, to protest his support of President George W. Bush and the Swift Boat campaign.

"Bob called me later and said, 'I really enjoyed that. They didn't know I was home, but I thought having those picketers out there was really fun,'" Mr. Miller said.