After the General Assembly redistricted the State Senate as required by the Virginia Constitution in 2011, Garrett decided to run in an open seat. The 22nd District was open due to the incumbent Republican Ralph K. Smith's home in Roanoke being drawn into another district. In the Republican primary, Garrett came in first in a five-person field with nearly 26% of the vote and a margin of fewer than 200 votes. During his time in office, he served on the General Laws and Technology, Courts of Justice, Education and Health, and Privileges and Elections committees.
In January 2017, Garrett was named to the House Committees on Foreign Affairs, Homeland Security, and Education and the Workforce. He is also a member of the conservative House Freedom Caucus, though he told voters during the campaign that he would not join the hard right group. Garrett is a member of the Republican Study Committee. In March 2017, Garrett posed for a photo with Jason Kessler, one of his constituents who was an organizer of the Unite the Right rally, a far-right rally held in August 2017 in Charlottesville, Virginia. The rally became the site of violent clashes leaving about 30 people injured, followed shortly by an incident in which a white supremacist rammed his car into a crowd, killing a woman and injuring another 19 other people. Following the violence at the rally, Garrett disavowed the organizer and said he was unaware of Kessler's role in the rally when they initially met.
2018 election
In the spring of 2018, reports surfaced that Garrett was using his congressional staff for personal use, leading his chief of staff to abruptly resign. Personal use of the staff time included running errands, house sitting, chauffeuring his kids and cleaning up after their dog. Rumors also spread that Garrett might not run again. Garrett clarified later that he intended to run in what long-time political analyst Larry Sabato called "one of the oddest" speeches. As of April 2018, Garrett was outraised by multiple Democratic opponents. In light of these fundraising numbers, the Cook Political Report moved the race from "likely Republican" to the more competitive "leans Republican." Democrats went on to nominate former investigative journalistLeslie Cockburn. On May 28, 2018, Garrett announced that he was seeking treatment for alcoholism instead of reelection.
Personal life
He resides in unincorporated Buckingham County with his wife, Flanna, and three daughters.