Santa Clara, CA (SportsNetwork.com) - The San Francisco 49ers will stay in- house for Jim Harbaugh's successor.

The team announced Wednesday that longtime defensive line coach Jim Tomsula has been elevated to the head coach's post vacated by Harbaugh's tumultuous departure for the University of Michigan.

Tomsula has been a Niners assistant since 2007 and worked under three head coaches -- Harbaugh, Mike Nolan and Mike Singletary -- over that stretch. He also served as the team's interim head coach for the 2010 season finale after Singletary was fired.

The 46-year-old will be formally introduced at a press conference scheduled for Thursday at Levi's Stadium.

"After conducting a thorough coaching search, and meeting with a number of outstanding candidates, Jim Tomsula clearly is the right man to lead this team," 49ers CEO Jed York said in a statement. "Jim is a great teacher and a tremendous mentor who conducts himself with great class and integrity."

Tomsula takes over a San Francisco squad that reached the NFC Championship Game in three straight seasons under Harbaugh from 2011-13, but is presently in a state of transition after parting ways with the new Michigan head coach following the conclusion of a disappointing 2014 campaign.

With rumors of friction between Harbaugh and the 49ers' front office swirling all throughout this past season, San Francisco dropped four of its final four games after a 7-4 start to miss out on the playoffs.

There were other off-field distractions the Niners had to deal with as well. Top pass rusher Aldon Smith was suspended for the first nine games for multiple violations of the NFL's personal conduct policy, while defensive lineman Ray McDonald was released in December after being investigated for an allegation of sexual assault.

Tomsula may be having to find two new coordinators during the offseason. Offensive play-caller Greg Roman accepted the same position with the Buffalo Bills earlier in the week, while it is unclear whether defensive coordinator Vic Fangio will return after being passed over for Tomsula for the head coaching nod.

The 49ers also had discussions with two-time Super Bowl champion head coach Mike Shanahan as well as Denver Broncos offensive coordinator Adam Gase before deciding on Tomsula.