While attending FAMU, she was arrested twice during protests to desegregate Tallahassee movie theaters. She also participated in the first civil rights demonstrations in Tampa, and was arrested in Washington, D.C. for her participation in civil rights activities.
In 1969, she served as a legal assistant to the Honorable Joe Lang Kershaw, the first African-American member of the Florida Legislature since Reconstruction and lead sponsor of the bill that created the Black Archives. Joyner has practiced law for more than 45 years.
She was first elected to the Florida House of Representatives in 2000 and later to the Florida Senate in 2006.
Today, she serves as the Florida Senate Democratic Leader for 2014-2016, making her the first black woman and the second woman ever to hold the position.
Til today, she remains the longest practicing Black woman lawyer in the history of Florida.