Carroll was born in Port of Spain, Trinidad and Tobago. She moved to the United States at the age of eight, and graduated from Uniondale High School in Uniondale, Long Island New York in 1977. She enlisted in the U.S. Navy in 1979. After serving as an aviation machinist's mate (jet engine mechanic), she was selected for the Enlisted Commissioning Program, becoming an Aviation Maintenance Duty Officer in 1985. She retired from the U.S. Navy in 1999 as a lieutenant commander.
In 1981, she received an Associate of Arts degree from Leeward Community College. She followed this in 1985 with a Bachelor of Arts in political science from the University of New Mexico. She moved to Florida in 1986. She received a Master of Business Administration degree from unaccredited and now defunct Kensington University in 1995. Carroll resigned her position on the National Commission of Presidential Scholars to accept a presidential appointment to the Veterans' Disability Benefits Commission. She then returned to school to earn an accredited Master of Business Administration degree online from St. Leo University in 2008.
Following her defeat in the 2000 election, she was appointed Executive Director of the Florida Department of Veterans Affairs by Republican Governor Jeb Bush and served in that post until July 2002. Republican President George W. Bush appointed Carroll to the Commission on Presidential Scholars from 2001 to 2004, and then a seat on the Veterans' Disability Benefits Commission from 2004 to 2007.
Carroll was appointed Deputy Majority Leader from 2003–2004, and served as Majority Whip in 2004–2006. She was Vice Chair of the Transportation and Economic Development Committee (2003–2004), Chair of the Finance Committee (2006–2008) and Chair of the Economic and Development Council (2008–2010).
Although cleared later, Carroll came under scrutiny for public relations work for a charity that involved itself in gambling and for $24,000 in income she failed to report on financial disclosure forms and her federal taxes that was a bookkeeper’s oversight she fixed during the investigation. She resigned her post as lieutenant governor on March 12, 2013, at the request of Governor Rick Scott. The Florida Department of Law Enforcement subsequently concluded that she did not break any laws.