Terms were not disclosed, but NFL.com reported it to be a five-year deal worth $32.5 million.
"Its official everyone. Taking my talents to Jacksonville," Robinson joked on his Twitter account Wednesday.
The 26-year-old wideout played 14 games for the Cowboys in 2011, starting six. He caught 54 passes for 858 yards and 11 touchdowns, all career-highs.
In five seasons with Dallas, St. Louis and Atlanta, the Illinois State product has recorded 143 receptions for 1,858 yards and 15 touchdowns in 52 contests (24 starts).