Berry, 29, gives the Orioles another left-handed bat for the outfield. He also presents a much-needed stolen-base threat after Nate McLouth signed with the Nationals as a free agent.
Berry is 29-for-29 in stolen base attempts, including the playoffs. He's a career .268/.339/.371 hitter in 107 games over parts of two major league seasons with the Tigers and Red Sox.
Berry went 5-for-8 with a home run, four RBIs, five runs and three steals with the Red Sox last season. He appeared in 94 games with the Tigers in 2012, batting .258/.330/.354 with 10 doubles, six triples, two homers, 29 RBIs and 21 steals.
The Orioles have reunited Berry with center fielder Adam Jones. They were teammates at Morse High School in San Diego and remain close friends.
Berry, who plays all three outfield positions, has a career .353 on-base percentage in eight minor league seasons. He played for three Triple-A teams last year - Toledo, Omaha and Pawtucket.
The Royals claimed Berry off waivers from the Tigers on June 4, and the Red Sox acquired him on Aug. 27 for pitcher Clayton Mortensen.
Berry, a career .277/.357/.372 hitter in the majors against right-handers, joins David Lough, Francisco Peguero, Julio Borbon and Xavier Paul as outfield additions in the offseason.
The Orioles are Berry's eighth organization since the Phillies selected him in the fifth round of the 2006 First-Year Player Draft.
"He's a good outfielder, an outstanding basestealer and he's shown good on-base capability, particularly against right-handed pitching," said Orioles executive vice president Dan Duquette.
"He's a capable player. He's got a lot of energy that he brings to a ballclub. He's got good legs and he's a good on-base man. He's really a good ball player."
Duquette just returned to his office after attending a private memorial service at Ruck's Funeral Home in Towson for former Orioles center fielder Paul Blair, who died last week at age 69.
"They did a nice job. It was a nice celebration of his life," Duquette said.
"He chose Baltimore as his community after he played here. He loved Baltimore. It was really a nice sendoff. His family, he had a lot of love in his life."
The list of former Orioles in attendance included Scott McGregor, Ken Singleton, Tippy Martinez, Joe Orsulak and Al Bumbry, who "gave a nice talk," Duquette said.
Hall of Famer Jim Palmer couldn't attend because of the snowstorm, but he sent a letter to be read.