The Costa Rica international has joined the Portuguese club on a season-long loan spell.
Boa Morte, who played for both Sporting and Arsenal during his career, claims that the loan move would prove to be beneficial for all parties, and Campbell will return to North London a much-improved player ahead of next season.
"He's exactly the type of player they need and he's exactly the player Sporting Lisbon were looking for," he told arsenal.com.
"He's got all the qualities to play for them and as long as he does well, I'm sure we'll be the beneficiaries here because he'll come back an even better player. That's the most important thing.
"He's really powerful when he drives forward with the ball on the right-hand side. He's definitely a handful for defenders."