On 2 September 2014, in the late hours of deadline day, Welbeck joined Arsenal on a "long-term deal" for a £16 million fee.
Stating the reason for his departure to a direct rival, Manchester United manager Louis van Gaal said "Welbeck doesn't have the record of Robin van Persie or Wayne Rooney.
We let him go because of Falcao, but also to allow the youngsters to fit in.
That is the policy.
That is why I am here."
Welbeck left Manchester United having made a total of 142 appearances, scoring 29 goals.

Welbeck made his Arsenal debut against the previous season's champions Manchester City at the Emirates Stadium in a 2–2 draw on 13 September.
Following his first two appearances for Arsenal, manager Arsène Wenger urged fans to be patient, saying: "Danny will improve—we don't have to make a problem of that.
We have to be patient with him".
Welbeck scored his first Arsenal goal against Aston Villa in a 3–0 win on 20 September, and also set up a goal for Mesut Özil.
On 1 October, he scored a UEFA Champions League hat-trick—the first treble of his professional career—against Galatasaray in a 4–1 victory.

On 9 March 2015, Welbeck scored the winning goal to knock out his former team, Manchester United, in the quarter-finals of the FA Cup at Old Trafford.
The following month, he was ruled out for the rest of the campaign with injury, missing the Gunners' victory in the 2015 FA Cup Final.
On 2 September 2014, in the late hours of deadline day, Welbeck joined Arsenal on a "long-term deal" for a £16 million fee. Stating the reason for his departure to a direct rival, Manchester United manager Louis van Gaal said "Welbeck doesn't have the record of Robin van Persie or Wayne Rooney. We let him go because of Falcao, but also to allow the youngsters to fit in. That is the policy. That is why I am here." Welbeck left Manchester United having made a total of 142 appearances, scoring 29 goals.
Welbeck made his Arsenal debut against the previous season's champions Manchester City at the Emirates Stadium in a 2–2 draw on 13 September. Following his first two appearances for Arsenal, manager Arsène Wenger urged fans to be patient, saying: "Danny will improve—we don't have to make a problem of that. We have to be patient with him". Welbeck scored his first Arsenal goal against Aston Villa in a 3–0 win on 20 September, and also set up a goal for Mesut Özil. On 1 October, he scored a UEFA Champions League hat-trick—the first treble of his professional career—against Galatasaray in a 4–1 victory.
On 9 March 2015, Welbeck scored the winning goal to knock out his former team, Manchester United, in the quarter-finals of the FA Cup at Old Trafford. The following month, he was ruled out for the rest of the campaign with injury, missing the Gunners' victory in the 2015 FA Cup Final.
Danny Welbeck