The deal announced Friday supersedes the $3.75 million, one-year contract the 26-year-old was awarded when he lost his salary arbitration case last month. There's a team option for 2025 at $15 million -- with a $2 million buyout -- that would make the deal worth $79 million over eight years.
The Reds started an overhaul in 2015, trading most of their top players for prospects. They have lost more than 90 games and finished last in the National League Central each of the past three seasons.
"We are sending a signal to the fans that the work that we've put in the last couple years is starting to come together," general manager Dick Williams said. "We're starting to identify the building blocks that we want to build this team around. Geno is one of them. We're ready to start winning again and we want Geno to be a part of it."
The 26-year-old gets a $2 million signing bonus payable within 30 days of the deal's approval by the commissioner's office and salaries of $2.25 million this year, $7 million in 2019, $9.25 million in 2020, $10.5 million in 2021 and $11 million each of the next three years.
It is the largest contract the Reds have agreed to during the rebuilding process.
Cincinnati obtained Suarez from Detroit in December 2014 as part of the trade that sent right-hander Alfredo Simon to the Tigers. Suarez was a shortstop earlier in his career, but the Reds moved him to third base after Todd Frazier was traded.
He has developed into a top third baseman, leading the NL in fielding percentage last season. He also batted .260 and had career highs with 26 homers and 82 RBIs. Suarez and the Reds began talking about a long-term deal before arbitration.
"It's an honor for me to be part of this wonderful team," Suarez said.
"Suarez has become a leader in our clubhouse," Williams said. "With the guys we've committed to -- Joey, Tucker and Geno -- these are the guys we can count on to lead."