Former Jamaican prime minister Edward Seaga in 2002, after voting in the general election. (Andres Leighton/AP)

Edward Seaga, a Jamaican record producer turned prime minister who forged closer ties to the United States and promoted austere, free-market economic policies while in office from 1980 to 1989, died May 28, on his 89th birthday.

His death was announced by Prime Minister Andrew Holness, a Seaga protege, who did not offer details. Mr. Seaga was being treated for cancer at a hospital in Miami, according to Jamaican media reports.

Mr. Seaga (pronounced see-AH-ga) was the only remaining member of the generation of Jamaican leaders who drafted the constitution when the Caribbean island gained independence from Britain in 1962. He won a parliamentary seat that year, representing West Kingston and remained in office for 40 years, longer than anyone in Jamaica’s history.

As minister of finance in the late 1960s, he spearheaded the development of the Jamaica Stock Exchange and Jamaica Citizens Bank. He then became opposition leader, and railed against the socialist agenda of then-Prime Minister Michael Manley, saying it crippled the island’s fragile economy.

For some older Jamaicans, Mr. Seaga is forever linked with the state-sponsored political violence of that era, when Jamaica’s two major political factions used gun-toting gangsters to sway voters.

Following a deadly 1978 military ambush of gang members allied to Mr. Seaga’s conservative Labour Party, Jamaica’s leading reggae musicians took the stage at a Kingston concert to support peace. The concert’s highlight was a moment that has become immortalized in Jamaican consciousness: Reggae icon Bob Marley made Mr. Seaga and Manley clasp hands over his head and promise an end to the violence.

It didn’t work; things only got bloodier. Clashes between partisans killed nearly 800 people before the 1980 election, a landslide victory for Mr. Seaga. He called it a “declaration against communism in Jamaica.”

Mr. Seaga went on to become President Ronald Reagan’s closest Caribbean ally and ushered in an era of relative prosperity, boosting a struggling economy that was hit hard by soaring inflation and widespread joblessness. But national debt soared.

In 1989, his party lost the general election to Manley, who positioned himself as a reformed centrist. Mr. Seaga remained Labour’s leader until 2005, building national institutions such as the annual festival celebrations, the Jamaica Cultural Development Commission and the HEART Trust/National Training Agency.

Edward Philip George Seaga was born in Boston on May 28, 1930. His parents were Lebanese Jamaican, and he renounced his U.S. citizenship at a young age to show his loyalty to Jamaica. He studied anthropology at Harvard University and published several papers on Afro-Jamaican folklore and obeah, a spiritual practice combining Christian and African rituals.

Before entering politics, Mr. Seaga was a major record producer who operated West Indies Records Ltd., which helped introduce ska to the world. At 29, he was appointed to Jamaica’s upper legislative house by Alexander Bustamante, the Labour Party founder and Jamaica’s first prime minister.

In the 1960s, Mr. Seaga gained fame for bulldozing an infamous slum and building Tivoli Gardens, the island’s first public housing project, which he filled with Labour supporters. The politicized complex became a hotbed of what Jamaica calls “garrison politics,” where vote-rich slums become permanent power bases for one party.

“Mr. Seaga can be blamed for starting garrison politics but not for the genesis of political violence,” said Christopher Charles, a senior lecturer in political psychology at Jamaica’s University of the West Indies.

He married Marie Constantine, a former Miss Jamaica, in 1965. They divorced in 1996, and Mr. Seaga married Carla Vendryes, a sociology researcher, the next year. In addition to his wife, survivors include three children from his first marriage, a daughter from his second, and several grandchildren.