Scanlon's mother was a small business owner and his father was a retired New York City Police officer.

[3] After graduating from Boston College in 2008, Scanlon worked as a Victim Advocate in the office of the New York County District Attorney before serving as an aide to Chris Murphy from 2009 to 2019.

[7] During his first term, Scanlon led the legislature's effort to combat Connecticut's opioid epidemic and became a leading voice on issues of mental health and addiction.

[8] In 2016 Scanlon wrote and sponsored legislation making Connecticut the second state in the nation to limit first-time opioid prescriptions to a seven day supply with exemptions for chronic pain as a way of reducing the number of unused and expired drugs in our communities.

[10] During four years as co-chairman, Sean wrote and passed legislation protecting people with pre-existing conditions from insurance discrimination[11] establishing the lowest monthly co-pay cap for insulin in the nation at $25[12] preventing insurance companies from covering mental health different than physical health[13] requiring health insurance plans to cover ten "Essential Health Benefits" such as maternity care and hospital visits[14] creating Connecticut's first prescription drug price transparency law requiring drug companies to justify large price increases[15] and instituting the first insurance and consumer safety standards for ride-share services like Uber and Lyft [16] In 2018, Scanlon worked with constituents Kristin and Mike Song to introduce Ethan's Law[17] in honor of their 15 year old son Ethan Song who was killed in a tragic gun accident.