Coley was born in Blountstown, and attended Chipola College and Florida State University, where she graduated with a degree in English education in 1984.

Coley then began teaching at Malone High School, where she worked until 1989, at which point she joined the faculty of Chipola College.

When her husband, State Representative David A. Coley, died, Marti Coley ran to succeed him in 2005 in the 7th District, which was based in the Florida Panhandle and included parts of Bay, Calhoun, Gadsden, Jackson, Leon, Liberty, Okaloosa, Wakulla, and Washington Counties.

In a special election on June 14, 2005, Coley defeated Democratic nominee Carl Joaquin Duncan with 81% of the vote.

"[1] Additionally, she supported legislation that would allow insurance companies operating in Florida to continue receiving tens of millions of dollars in tax breaks, declaring that the bill "helps us not raise taxes, enables us to support business like we all like to do, so that we have jobs for our citizens.