Lt. Col. Leilani Tydingco-Amarante received her commission as a Signal Corps officer from the Reserve Officer Training Corps in 1998 in Philadelphia, Pennsylvania. While in the Signal Corps, she held several staff positions, including the 122nd Signal Battalion training officer (2nd Infantry Division, Korea), 302nd Brigade Support Battalion (BSB) signal officer (2nd Infantry Division, Korea), company executive officer for the Defense Information School (Fort Meade, Maryland), and the 54th Signal Battalion operations officer (Kuwait and lraq). In addition, she held company command positions with the 54th Signal Battalion and the 302nd Brigade Support Battalion.

Tydingco-Amarante was assessed into the Acquisition Corps with a focus in program management in 2008, before being assigned to Fort Hood, Texas, as a test officer for the Operational Test Command. In 2011, she completed a one-year assignment in Afghanistan as the operations officer for Task Force Biometrics. In 2012, she served in assistant product manager positions on Fort Belvoir, Virginia, with Force Protection Systems and Automated Movement and Identification Solutions. During this time, she also served as data chief with Army Enterprise Systems Integration Programs.

Currently, Tydingco-Amarante serves as the product manager for Cyber Analytics and Detection at Defensive Cyber Operations within the Program Executive Office Enterprise Information Systems. Prior to this role, she was a program analyst to the Deputy Under-Secretary of the Army - Test and Evaluation.

Tydingco-Amarante's awards include the Bronze Star Medal (1), Meritorious Service Medal (5), Army Commendation Medal (1) and the Army Achievement Medal. She holds a Master of Business Administration from Webster University, level 3 certification in program management and level 2 certification in test and evaluation.