A Bluefield native, Giardina grew up in a McDowell County coal company town before moving to Kanawha County. Her background in the region has strongly influenced her literary works, particularly those focused on the struggles of coal miners .

Her literary career began with historical fiction. Her first book, Good King Harry (1984), explored the life of Henry V. Her later works, including Storming Heaven (1987) and The Unquiet Earth (1992), are set in West Virginia and focus on the lives of coal miners, addressing the region’s socioeconomic struggles and the Mine Wars. Storming Heaven won the Weatherford Award, and The Unquiet Earth earned both the Lillian Smith Award and an American Book Award.

Giardina's novels, such as Saints and Villains (1998), about the life of Dietrich Bonhoeffer in Nazi Germany, and Fallam’s Secret (2003), which explores time travel, showcase her range and ability to tackle complex historical and philosophical themes. Her most recent work, Emily's Ghost (2009), is a historical novel based on the life of Emily Brontë.

She is an ordained Episcopal deacon, reflecting her engagement with faith and social justice. Her activism, notably in support of labor rights and environmental issues, has paralleled her literary work. She ran for governor of West Virginia in 2000 as a candidate for the Mountain Party, focusing on issues like surface mining and mountaintop removal.