[7] During this time, Aranda visited a friend who was attending California Lutheran University, and soon enrolled there in an attempt to return to play.

[7] While his injuries made it impossible for him to play, he got an opportunity to become a student assistant while an undergraduate, serving as linebackers coach for the Kingsmen from 1996 to 1999.

[9] He also sought out coaches to talk about the profession, and became enamored with the book Thinking Body, Dancing Mind by sports psychologist Jerry Lynch, who has consulted with numerous championship teams in several sports and whose thinking has influenced coaches such as Phil Jackson and Steve Kerr.

[6] While back in Southern California during an offseason break in 2001, Aranda cold-called Lynch and asked for a face-to-face meeting with him in Santa Cruz, about 300 miles from Redlands.

He then returned to Cal Lutheran as defensive coordinator and linebackers coach, positions he held for the 2005 and 2006 seasons.

[10] In Aranda's first season, he cultivated a talented unit that included David Veikune, Joshua Leonard and Keala Watson.

In 2009, Aranda was credited with developing a creative defensive scheme that stymied Navy's vaunted rushing attack and allowed the Warriors to earn a 24–17 victory over a Midshipmen squad that defeated Notre Dame two weeks earlier.

[10] In those wins, Aranda's opportunistic defense limited the opposition to 16.1 points per game, only allowed 2.4 yards per rush [10] and held Colin Kaepernick in check en route to handing the Nevada Wolf Pack its only loss of the season.

Under Aranda's guidance the Warriors led the nation in turnovers caused (38) and tied a school record for most defensive touchdowns (5).

[11] Leading up to the game, Colorado coach Jon Embree boasted that as to Hawaii's defense, the Buffaloes were going to "run the ball down their throat.

"[12] Aranda, who later acknowledged that he took Embree's comment personally, met the challenge head on and limited the boastful Buffaloes to just 17 net rushing yards on the night.

[14] At the conclusion of the season, he found himself on the wrong-side of the ledger and was fired after head coach Greg McMackin resigned.

[28] On January 1, 2016, it was announced that Aranda was hired to replace Kevin Steele as defensive coordinator for the LSU Tigers.

After the season concluded, Aranda and Baylor parted ways with the Bears' first year offensive coordinator, Larry Fedora, and then later hired Jeff Grimes from Brigham Young University for the same role.

The Bears were ranked in the top 25 for the majority of the 2021 football season and finished with a 12–2 record (7–2 in Big 12 play), the most wins in program history.