Sin returned to her native Sacramento in 2005 after receiving an honorable discharge and immediately began her undergraduate studies in History. Upon her graduation from Sacramento State with a BA in History, Magna Cum Laude, in 2008, Sin became the Lead Certifying Official for veterans services at American River College. She continued her work with veterans at Sacramento State as the Veterans Benefit Advisor and Certifying Official, focusing on developing programs for student veterans.
Lindsey Sin was appointed as Deputy Secretary for Women Veterans Affairs by Governor Edmund G. Brown Jr. on November 22, 2011. Sin enlisted in the United States Navy in 1997 as a Cryptologic Technician Interpretive. She completed two flight tours in Rota, Spain during which time she deployed in support of Operations Northern Watch, Southern Watch, Enduring Freedom and Iraqi Freedom and achieved the rank of Petty Officer First Class.