"I've been wrongly accused and I'm going to be totally exonerated when the evidence comes out," Morrissey told reporters at a Tuesday news conference outside the Henrico County courthouse.
The Democratic lawmaker was charged Monday with five counts related to what a special prosecutor alleged were multiple sexual encounters with a 17-year-old teenage girl at the legislator's law office in August 2013.
The charges are built largely on text messages that Spotsylvania County Commonwealth's Attorney William Neely said Morrissey and the girl exchanged with each other and their friends.
Morrissey, 56, of Henrico County, said the text messages were fakes, and that his and the girl's phones were hacked by a woman who has harbored a deep attraction to the girl.
"Our experts have uncovered the hacking device, the serial number, and the texts," Morrissey said.
In court papers filed Monday, Neely said law enforcement agencies have found no evidence that the phones belonging to either Morrissey or the teenage girl were hacked.
Morrissey's comments came on the same day that Del. Mark L. Keam, also a Democrat, called on Morrissey to resign.
"The job requires each of us to uphold the highest standard of ethics in order to earn and to retain our constituents' trust in their government," Keam said in a written statement.
But no other lawmaker publicly joined Keam in calling for the resignation of Morrissey, one of Virginia's most outspoken lawmakers.
House Democratic Caucus Chairman Del. Mark Sickles said his caucus "believes in everybody getting a fair trial."
"I hope he's innocent," said Sickles.
House Speaker William J. Howell, a Republican, declined to comment about Morrissey. Under the Virginia Constitution, a two-thirds vote is necessary for the House to expel one of its members.