[1] Reilly was born in Ohio on June 26, 1958, and later moved to Essex, Maryland, where she attended Kenwood Senior High School.

From 2008 to 2013, she served as the chief of staff to state delegate H. Wayne Norman Jr. She is currently a member of the Republican Club of Cecil County.

[4] She won the Republican primary in June 2014, placing second behind Andrew Cassilly,[5] and defeated Democrats Jeffrey Elliott and Daniel Lewis Lamey in the general election.

[9] During the 2016 legislative session, Reilly introduced a bill to dedicate a portion of Route 924 as "Heroes Highway" after two slain police deputies.

[10] In 2018, Reilly introduced legislation to sentence people convicted of selling opioids that result in a minor's death to up to 30 years in prison.

[13] In April 2020, Reilly co-signed a letter calling on the Maryland Department of Health to share data on the 2,000 inmates released during the COVID-19 pandemic.