Ledgett has an undergraduate degree in psychology and a graduate degree in strategic intelligence.
In 1988, he began working for the National Security Agency, where he served in a variety of positions in the cybersecurity division.
Previous positions at NSA included Deputy Director for Analysis and Production (2009–2010), Deputy Director for Data Acquisition (2006–2009), Assistant Deputy Director for Data Acquisition (2005–2006), and Chief, NSA/CSS Pacific (2002–2005).
From 2012 to 2013 he was the Director of the NSA/CSS Threat Operations Center, responsible for round-the-clock cryptologic activities to discover and counter adversary cyber efforts.
From June 2013 to his appointment as Deputy Director in January 2014, Ledgett headed the investigation of leaks regarding NSA surveillance programs made by Edward Snowden. During this time he argued for amnesty for Snowden in exchange for the return of the remaining classified documents still in his possession.
On February 3, 2017, Ledgett announced that he would be retiring in the spring. His successor was George C. Barnes.
On August 15, 2017, Ledgett was elected to M&T Bank Corporation's Board of Directors.
Ledgett pledged increased transparency regarding NSA operations. However, he defended the operations of the NSA and argued in a rare interview with Reuters that NSA operations are completely legal. Ledgett also accused the media of sensationalizing reports about various NSA mass surveillance programs.
In March 2014, Ledgett stated during a TED Talk that the NSA operates legally. He further argued that President James Madison would be proud of the way in which Constitutional checks and balances have governed NSA mass surveillance.