Hickson was waived by Sacramento on Monday. The Kings acquired him last June from Cleveland for forward Omri Casspi and a conditional future first-round draft pick. He played 35 games for the Kings, averaging 4.7 points and 5.1 rebounds in 18.4 minutes per contest.
Golden State and Phoenix had also been reported to have interest in the 6-foot-9 Hickson, who had been bothered recently by back spasms and had played only six minutes in the past 10 games.
Hickson was a first-round pick by Cleveland out of North Carolina State in 2008. For his career, he has averaged 8.5 points and 5.6 rebounds per game.
Trail Blazers owner Paul Allen confirmed the move via Twitter.
It was not known if Hickson would be able to join the team for its game against the Memphis Grizzlies on Thursday night at the Rose Garden. Portland has lost nine of its last 12 games.
The addition of Hickson was the latest in a flurry of recent moves by the Blazers, the most notable being the dismissal of head coach Nate McMillan after six-plus years with the team.
McMillan was fired last Thursday, when the Blazers also pulled off two deals at the NBA's trade deadline.
Portland traded veteran center Marcus Camby to Houston in exchange for guard Jonny Flynn, center Hasheem Thabeet and a second-round pick in the NBA draft. The Blazers also sent forward Gerald Wallace to New Jersey in exchange for center Mehmet Okur, forward Shawne Williams and a first-round draft pick.
Portland also waived often-injured center Greg Oden, the No. 1 draft pick in 2007, and made 33-year-old assistant coach Kaleb Canales interim head coach.
In addition to claiming Hickson, the Blazers waived Okur on Wednesday.