Chacin’s $15.5 million, two-year deal and Gallardo’s $2 million, one-year agreement were finalized by Milwaukee on Thursday.
Chacin, who turns 30 in January, went 13-10 with a 3.89 ERA in 32 starts last season for San Diego.
"I have been really working hard to get to the point where I can pitch and don’t think about anything (except) making outs, making my pitches," Chacin said. "I was able to do that — just go out and have fun pitching."
He gets a $1.5 million signing bonus payable within 45 days of the contract’s approval by the commissioner’s office and salaries of $8 million next year and $6 million in 2019.
Gallardo, 32 in February, was selected by Milwaukee in the second round of the 2004 amateur draft and was 89-64 with a 3.69 ERA in eight seasons with the Brewers through 2014. He pitched for Texas the following year, Baltimore in 2016 and Seattle last season, going 5-10 with a 5.72 ERA.
"We all know that the last couple years haven’t gone (well) for me," Gallardo said. "I think it’s just a matter of minor adjustments."
Gallardo can earn $1.75 million in performance bonuses based on innings: $100,000 each for 50, 65 and 80; $150,000 apiece for 95 and 110; $200,000 each for 125 and 140; and $250,000 apiece for 155, 170 and 185,
He can make $250,000 for games pitched: $50,000 each for 30 and 40, and $75,000 apiece for 50 and 60.
Milwaukee has sought starters. Right-hander Jimmy Nelson is recovering from right shoulder surgery on Sept. 12, four days after he was hurt while diving back to first after rounding the base on a single.
General manager David Stearns didn’t rule out bringing in more pitching.
"I think it’s a combination of eating innings and getting outs. Both Jhoulys and Yovani throughout their careers have demonstrated that they have the capability of doing that," Stearns said.