Smith, 27, the MVP of Super Bowl XLVIII while with the Seattle Seahawks, will sign a five-year contract, the 49ers said in a Thursday news release. He is coming off consecutive triple-digit-tackle seasons for the first time in his six-year career. He led the Raiders in 2016 with 115 tackles and also had an interception and forced two fumbles, recovering one.
Gould, who will sign a two-year deal, was signed by the Giants in October when they released Josh Brown following his admission of domestic violence. Gould, 35, made all 12 of his field goal attempts (including the playoffs), with a long of 47 yards. He made 21 of 24 extra points.
The 49ers also said they had agreed to contract terms with receiver Pierre Garcon on a five-year deal, receiver Marquise Goodwin on a two-year deal, quarterback Brian Hoyer on a two-year deal, fullback Kyle Juszczyk on a four-year deal and tight end Logan Paulsen on a one-year deal.
Smith, who became a full-time starter upon landing in Oakland as a free agent two years ago, has been solid for the Raiders, though far from spectacular. He has worn the green-dot helmet as the defensive signal-caller.
Still, while Smith, who had a base salary of $3 million in 2016, led the Raiders in tackles last season, his production went down dramatically from the previous season, from 143 tackles to 115 and four sacks to none.
The lack of results as a pass-rusher were glaring for the weakside linebacker -- the Raiders had the fewest sacks in the league last season with 25 despite the presence of NFL Defensive Player of the Year Khalil Mack. Smith also struggled in coverage.
Gould, a Penn State product, spent the first 11 seasons of his NFL career with the Chicago Bears, for whom he became one of the most accurate kickers in league history. Gould made 85.9 percent of his kicks with the Bears and Giants, placing him seventh on the all-time list.
Gould made the Pro Bowl and was named All-Pro after making 89 percent of his kicks during the 2006 season.
The beloved kicker was released by Chicago in a surprise move before the start of last season. He waited for the right opportunity before signing with the Giants and reaching the playoffs for the first time since the 2010 season.
Information from ESPN's Paul Gutierrez and Jordan Raanan was used in this report.