Vallario is a past president of the Prince George's County Criminal Trial Lawyers Association and a member of the Order of Sons of Italy in America.

[1] He was featured in the Netflix documentary, "The Keepers," for his role in being opposed to a bill seeking to increase the statute of limitations of sexual abuse victims.

He was the Co-Chair of the Task Force to Examine Crime Victims' Rights Laws in Maryland (1996–2003), a member of the Special Committee on Gaming (2001), a member of the Maryland State Commission on Criminal Sentencing Policy and the past chair, Prince George's County Delegation.

Vallario has been an active supporter of victims rights as well as a proponent for strengthening Maryland's laws against child predators.

"[4] Vallario was attacked in a lengthy Washington Post article published August 3, 2013, for his conflict of interest in having legally represented many drunken drivers and then using his Chairman position to pardon them.