Sanu was originally drafted by the Cincinnati Bengals in the third round (83rd overall) of the 2012 NFL Draft. Throughout his nine-year career with the Bengals (2012-15), Atlanta Falcons (2016-19), New England Patriots (2019), 49ers (2020) and Detroit Lions (2020), he has appeared in 128 games (96 starts) and registered 420 receptions for 4,694 yards and 27 touchdowns. He has also recorded 42 carries for 226 yards and two touchdowns on the ground and completed seven of eight passing attempts for 233 yards and four touchdowns through the air. Sanu has also appeared in nine postseason games (eight starts) and added 26 receptions for 318 yards and two touchdowns.
As a true freshman at Rutgers, Sanu recorded 51 receptions for 639 yards, three touchdowns and rushed 62 times for 346 yards and five touchdowns. In 2009, Sanu was named the St. Petersburg Bowl MVP after defeating the University of Central Florida, 45-24.
In 2011, Sanu broke Larry Fitzgerald's Big-East single-season reception record with 115 receptions for 1,206 yards.
Sanu has a history in Kyle Shanahan's offense. The receiver played under Shanahan during the Atlanta Falcons 2016 Super Bowl run. "He moves a lot of different pieces and playmakers that he likes to get involved," Sanu said of the intricacies of Shanahan's playbook. "He likes to disguise certain things to get the ball to the person he wants. He's great at it. It's pretty cool to see how he does it."
In his rookie season with the Bengals in 2012, Sanu came into the game against the Washington Football Team in the Wildcat formation. In the first play from scrimmage, he threw a 73-yard touchdown pass to A.J. Green, becoming the first Bengals wide receiver to ever throw a touchdown pass.
Also a track and field athlete at Rutgers, Sanu was one of the state's top performers. At the 2008 NJSIAA Sectional Championships, he placed 2nd in the triple jump and 3rd in the long jump. He also competed as a sprinter, recording personal-bests in the 55 meters and 200 meters at the 2008 Merli Invitational.