In 2006, Maualuga became a regular starter at middle linebacker. He played all 13 games for USC, starting 10 of them. He finished the season with 78 tackles and two sacks. He also had an interception and three pass deflections. His 78 tackles were second on the team, behind only Keith Rivers. He set a career high with 11 tackles in USC's win over Nebraska. He was one of 10 semifinalists for the Butkus Award as the best linebacker in the nation.
He followed up his all-Pac-10 2006 season by repeating the honor in 2007. He started 12 of 13 games in his junior season, finishing with a team-leading 79 tackles and six sacks, good for third on the Trojans defense. He capped off the season by recording three sacks against Illinois in the 2008 Rose Bowl, earning Defensive MVP honors.
Maualuga made the leap from All-Pac-10 to All-America in 2008, finishing the season with 79 tackles and two interceptions. He was USC's leading tackler for the second straight season. He recorded a season-high 12 tackles in USC's upset loss to Oregon State. After the season, he was honored as a consensus first team All-America and won the Bednarik Award as the nation's top defensive player. He was also a finalist for the Butkus Award, which went to Aaron Curry of Wake Forest. After the 2008 season, Maualuga was invited to participate in the 2009 Senior Bowl, where he recorded three total tackles (1.0 for loss) and forced a fumble in a winning effort for the South team.
He was selected in the second round (38th overall) of the 2009 NFL Draft by the Cincinnati Bengals. Before the 2009 season, Maualuga signed a four-year contract with Cincinnati. He played 15 games for the Bengals as a rookie, finishing with 63 total tackles and three forced fumbles. He suffered a broken ankle against the Chiefs in Week 16, forcing him to end the season on injured reserve and miss the Bengals postseason.
On Jan. 29, 2010, shortly after his rookie season with the Bengals, Maualuga was arrested and charged with drunken driving and careless driving. Police determined that Maualuga was behind the wheel when a car struck two vehicles and a parking meter. Maualuga has pleaded not guilty to the charges.