Humber went 5-5 with a 6.44 ERA in 16 starts for the White Sox last season and made headlines when he threw a perfect game against the Seattle Mariners on April 21.
The signing is a homecoming or sorts for Humber, as he and his family live 175 miles north of Houston in Tyler, Texas, and the 29-year-old is a former standout at Rice University. Humber was a member of the Owls' 2003 national championship team, was a First-Team All-American in 2004 and ranks second in school history in strikeouts and third in wins.
"It's really exciting, more so for my family than anything," Humber told MLB.com. "The places I've played before, they haven't been able to see me but a little bit, but I'll be right up the road no now in Houston. So we're excited about it. My wife and I have a little baby and it will make it easier on them as far as traveling and everything. I think it's going to be a good situation."
In 44 career starts, Humber is 16-15 with a 4.87 ERA. He is expected to compete for one of the final two spots in the Astros' starting rotation next season.