Born and raised in Plantation, Florida (near Fort Lauderdale) of Norwegian heritage, Carl was the first of four children and the son of a lawyer, Odel and teacher, Patricia. He married Connie Lyford just after high-school graduation and entered Emory University in 1970, where he contributed numerous satiric pieces to the school newspaper, The Emory Wheel. In 1972 he transferred to the University of Florida, graduating in 1974 with a degree in journalism. Hiaasen divorced Lyford in 1996 and remarried in 1999 to Fenia Clizer, a restaurant manager. He has one son from his first marriage and another from his second.

After two years as a reporter for Cocoa Today out of Cocoa, Florida, he joined the Miami Herald in 1976, where he still (as of 2006) works. From 1979 he turned to investigative journalism, concentrating on construction and property development - exposing schemes to destroy, for profit's sake, Florida's natural beauty. From 1985 he has had a column in the Herald, initially thrice-weekly it now appears once a week.

Eventually, in the 1980s, he embarked on a career as a novelist. He co-wrote three thrillers with fellow-journalist Bill Montalbano (Powder Burn (1981), Trap Line (1981), A Death in China (1986)). After Montalbano became a foreign correspondent, Hiaasen wrote his first book, Tourist Season (1986) - introducing many of his distinctive styles and themes.

Hiaasen's fiction mirrors his concerns as a journalist and Floridian. His novels have been classified as "environmental thrillers" and are usually found on the crime shelves in bookshops, although they can just as well be read as mainstream satires of contemporary life.

Hiaasen's Florida is that of greedy businessmen, corrupt politicians, dumb blondes, apathetic retirees, intellectually challenged tourists, and militant ecoteurs. It is the same Florida of John D. MacDonald and Travis McGee, but aged another 20 years and viewed with a more satiric or sardonic eye.

Critics have complained that Hiaasen's work is essentially the same novel repeated ad nauseam, only with different characters. His fans would reply that although the plots in the novels seem to follow a familiar line - with a beautiful part of Florida being threatened by corporate baddies and an enigmatic hero saving the day - the startling diversity and quirks of the characters more than make up for any lack of imagination in the author's plots.