He also had two forced fumbles and an interception. Smith earned an overall grade of 44.3 from Pro Football Focus, which ranked 60th among all qualifying linebackers in 2015. Head coach Jack Del Rio retained Smith as the starting weakside linebacker to start 2016, along with Bruce Irvin and middle linebacker Ben Heeney. Smith was inactive for the Raiders' Week 5 win against the San Diego Chargers due to a quadriceps injury. In Week 11, Smith collected ten combined tackles (nine solo), made a pass deflection, and intercepted a pass by Brock Osweiler during a 27–20 victory against the Houston Texans in Mexico City. On January 1, 2017, Smith recorded a season-high 12 combined tackles (nine solo) as the Raiders lost 24–6 at the Denver Broncos in Week 17. He finished the 2016 season with 103 combined tackles (86 solo), three pass deflections, two forced fumbles, and an interception in 15 games and 15 starts. Smith's performance suffered in 2016 and he earned an overall grade of 46.3 from Pro Football Focus. His grade ranked 68th among 88 qualifying linebackers during the season. On March 9, 2017, the San Francisco 49ers signed Smith to a five-year, $26.50 million contract with $11.50 million guaranteed and a signing bonus of $7 million. Smith entered training camp slated as the starting right outside linebacker, but saw competition from rookie first round pick Reuben Foster. On August 5, 2017, Smith injured his pectoral during a training camp practice held in Levi's Stadium. On August 7, 2017, the San Francisco 49ers officially placed Smith on injured reserve after an MRI determined he had suffered a torn pectoral muscle. He remained on injured reserve throughout the entire 2017 season. In 2018, he appeared in 12 games, tallying 35 tackles (22 solo) and one pass defensed. On August 27, 2019, Smith was released by the 49ers. On October 22, 2019, Smith was signed by the Jacksonville Jaguars. He appeared in 2 games as a backup. He was released on November 5. On December 17, 2019, Smith was signed as a free agent by the Dallas Cowboys to provide depth because of injuries for the last 2 games, reuniting with his former defensive coordinator Kris Richard. He appeared in 2 games with one start, registering 5 tackles and one forced fumble. He was not re-signed after the season. Smith's brother Steve Smith also attended USC from 2003 to 2006 and played wide receiver for the New York Giants, Philadelphia Eagles, and the St. Louis Rams.