Texas president Greg Fenves introduced Perrin at a Wednesday news conference in Austin.
"Everybody I've talked with that knows Mike says he has absolute integrity and confidence in his ability to lead our great athletics department," Fenves said.
Perrin, a former Texas linebacker and a Houston-based attorney, has been involved with UT athletics for more than 30 years on a volunteer basis and is confident his leadership experience gained from his law career makes him well-prepared to deal with the issues facing the athletic department in the wake of Patterson's exit.
He said repairing the relationship between Texas and its fans will be a priority during his time overseeing athletics.
Perrin attended the Longhorns' 42-28 win over Rice last week and enters the job determined to reconnect with the fan base. Texas reportedly has roughly 11,000 tickets still available for its home game against Cal this Saturday.
"I've been concerned. I sat in the stands last week and saw empty seats," Perrin said. "It concerns me that fans last week voted with their feet."
Perrin met with Texas coaches on Wednesday, and he and Fenves both offered their full support for football coach Charlie Strong and said they stand firmly behind UT's coaches.
Perrin said he's had several opportunities to spend time with Strong and has been "so impressed" by his leadership in rebuilding the program.
"We just hit it off," Perrin said. "He's the real thing in terms of humanity, dedication to education, devotion to his craft. He's the kind of coach that players want to follow and play hard for. ... I consider him a personal friend and I look forward to continuing to support him."
Perrin knows the timing of his arrival does complicate his ability to make changes in the athletic department, particularly in addressing the football ticket pricing issues of Patterson's stint as AD, but he will reevaluate the policies of his predecessor.
"I don't personally plan to undo what is in place," Perrin said. "We've got a season underway, a school year underway, we've got things in place. I do think some of the people that have spoken to me have expressed a desire to revisit some of those issues."
Perrin signed a one-year deal and said he'll serve as interim AD as long as he's needed. He admitted he was first approached by Fenves about the interim AD position on Labor Day.
A timetable for hiring the full-time replacement has not been determined, and a search may not begin "until early next year" because of the difficulties involved in talking to candidates during football season, a source told ESPN's Brett McMurphy.
Texas women's athletic director Chris Plonsky said Wednesday she has no interest in being a candidate for the full-time replacement.