Because the UAB program is shutting down, the sophomore will be eligible to play immediately.
"There was something about Indiana I just liked," Howard told ESPN.com. "And it was big with them having a 2,000-yard running back the previous year and most of the offense coming back."
Howard's announcement comes just three days after Indiana tailback Tevin Coleman -- who rushed for a school-record 2,036 yards -- declared early for the NFL draft. In a news release, Hoosiers coach Kevin Wilson called Howard "our top target."
Wilson visited with Howard on Tuesday, and Howard said that's when he committed. Indiana was the first school to reach out to Howard, via Twitter, and Howard said he eventually trimmed his choices down to Vanderbilt and IU.
"I'm not here to replace Tevin Coleman's production," Howard said. "I'm here to do the best I can."
The university announced the move Thursday afternoon.
Howard, an Alabama native, rushed for 1,587 yards and 13 touchdowns this season. In 2013, he set the UAB single-season freshman record with 881 rushing yards.
"We recruited him very, very hard and we are excited he is joining us," Wilson said in a news release. "The sign of a good program is finding good players to replace good players, and we have done just that."