The deal with the burly 7-footer was first reported on July 3, but it could not be formally announced by the team until Thursday per NBA rules. The Blazers used a midlevel exception on the contract, worth a reported $9.8 million.
Kaman has averaged 11.7 points, 7.9 rebounds and 1.4 blocks over an 11-year NBA career. He is expected to back up Robin Lopez with the Blazers.
''We targeted Chris early in the process believing his offensive versatility and defensive presence would make for a quality addition to our front court,'' Blazers general manager Neil Olshey said in a statement. ''His skill set complements our returning roster players and we expect him to have an immediate impact.''
Kaman spent last season with the Los Angeles Lakers, averaging 10.4 points and 5.9 rebounds, but was limited to a career-low 18.7 minutes in 39 games. He struggled late in the season with injuries.
Kaman was introduced at a press conference Thursday with another Portland free-agent acquisition, guard Steve Blake.
''Having played 11 years already, I've experienced the ups and the downs,'' he told reporters. ''I wanted to go somewhere where I felt like I would fit and actually help a team - not kind of go to a team where they were trying to build or maybe not build and get stuck back on the bench or play a small, small role. I wanted to go somewhere where I could actually help a team.''
Kaman was the sixth overall pick in the 2003 draft by the Los Angeles Clippers. The Michigan native, who played at Central Michigan, was an All-Star with the Clippers in 2010, averaging a career-high 18.5 points and 9.3 rebounds, before he was traded to New Orleans the next season.
He played for the Dallas Mavericks in 2012-13 before signing a one-year deal with the Lakers. The Blazers will be his fifth team.
He will wear No. 35 in Portland.
The Blazers went 54-28 last season, advancing to the Western Conference semifinals before losing to eventual NBA champion San Antonio.