Porter replaces Tommy West, who was fired Nov. 9 after nine seasons. West coached the Tigers (2-10) the rest of the season, which ended with a 33-30 overtime loss at Tulsa on Friday.
"The Memphis job is the perfect job in the perfect place for me," said Porter, who accepted the job late Friday night. "I understand the Memphis brand. I believe in it unconditionally. I have a conviction, a passion about it, and a vision that allows me to walk into homes in this community, talk to the student body and faculty and get them to believe in that vision."
Porter ranks sixth in career rushing at Memphis with 2,194 yards, and scored 20 touchdowns from 1990-93. He later coached at Tennessee-Martin, Arkansas State and Oklahoma State before joining Les Miles at LSU, where Porter has coached running backs since 2005.
"I remember this young coach when he interviewed for a job at Oklahoma State," Miles said. "He had a great attention to detail, had a great presentation and just understood exactly how to do the job. I always interview four or five guys and he was just a standout."
In the last week, Washington Redskins assistant coach Jerry Gray also emerged as a finalist. He has ties to FedEx founder Fred Smith, a Memphis supporter whose son Arthur was a quality control assistant for the Redskins. Another son, Cannon Smith, transferred to Memphis earlier this year and is expected to compete at quarterback next season.
But athletic director R.C. Johnson said he decided to pick "the best possible candidate in the quickest amount of time. I think we have done that."
Before Johnson even introduced Porter at Sunday afternoon's press conference, the new coach received a standing ovation from the Tiger fans who had gathered for the announcement.
Porter stood and clapped with the throng to the school fight song.
The 37-year-old coach was considered one of the top candidates as soon as West was dismissed, after going 49-61 and taking the Tigers to five bowl games in six years. Porter has never served as an offensive coordinator or head coach, but those shortcomings were offset by his ties to Memphis, his reputation as a recruiter and his success at LSU.
"He has done nothing but grow in experience and in capabilities," Miles said. "I have had some assistant head coaches, but none like Larry Porter."
While he has a reputation as a strong recruiter, some have wondered if those talents can translate from a BCS program like LSU to a school like Memphis, which plays in Conference USA.
The school is located in the heart of the Southeastern Conference and must compete with Mississippi, Mississippi State, Tennessee and Arkansas for players.
Porter said his familiarity with the city is a benefit in that respect, and he plans to start meeting with local high school coaches Monday.
"We have enough talent here in the city of Memphis to create a strong foundation for this program," Porter said. "That's why we have to start with our base of recruiting right here in Memphis. Let's go raid Memphis and get these kids to stay home. Let them understand they're going to be part of the reason why we are a championship-caliber program."
Porter said he had thought about coaching the Tigers ever since watching their basketball team play Kansas in the 2008 national championship game.
At the time, LSU was visiting the White House to be honored for its national championship in football. Porter said he thought the Memphis football program could reach the same level, and he wanted to be a part of that if the position came open.
"In terms of selling your program and believing in something, you have to have a conviction," Porter said. "I don't think we should be in a position where we have to take a backseat to anybody."