On 6 July 2009, French newspaper L'Equipe announced that Bordeaux president Jean-Louis Triaud had reached an agreement with English club Manchester United for the transfer of Obertan with Triaud stating that an agreement had been reached several weeks ago and that the player had agreed contract terms.
The following day, Obertan successfully passed his medical in Manchester and, on 8 July, signed his contract officially making him a Manchester United player.
The transfer fee was undisclosed, but is believed to be in the region of £3 million, with Obertan joining the club on a four-year deal.

However, at the start of the 2009–10 season, Obertan suffered a setback when he suffered a spinal problem that kept him on the sidelines for a month.
Following three games for the Manchester United reserve team, including a 3–0 win over Oldham Athletic on his debut, Obertan made his senior debut in the club's 2–0 away win over Barnsley in the League Cup fourth round on 27 October.
He made his Premier League debut for Manchester United on 31 October, coming on as a substitute in the 2–0 win over Blackburn Rovers at Old Trafford.
His Champions League debut came that same week, replacing Federico Macheda in the 82nd minute in the 3–3 home draw against CSKA Moscow on 3 November 2009.
On 8 December, Obertan set up the second of Michael Owen's hat-trick in a 3–1 away victory at Wolfsburg in the Champions League, taking on 3 players before teeing Owen up for a simple tap-in.
On 15 December, Obertan made his first league start for United, being replaced in the 71st minute by Danny Welbeck in a 3–0 home win over Wolves.
In his first season at Manchester United, Obertan made 13 appearances in all competitions.

Obertan scored his first goal for United in a 1–0 win over Philadelphia Union on 21 July 2010 on the club's pre-season tour of North America.
Just one week later Obertan was forced to miss the start of the new season as he was injured midway through the first half during United's 5–2 victory in the 2010 MLS All-Star Game.
On 22 September, Obertan made his return from injury, replacing Javier Hernández in the 68th minute of United's 5–2 away League Cup win over Scunthorpe United.
Obertan's first official goal for United came on 2 November, netting the second of a 3–0 away win over Bursaspor in the Champions League, this also being Obertan's first European goal.
With Manchester United finished the 2010–11 season as Champions, Obertan made six appearance for the club, which
Ahead of the 2011–12 season, with his first team place increasingly limited, Newcastle United confirmed their interest in signing Obertan as a direct replacement for Joey Barton, as Manchester United planned a rebuild of their squad.
On 6 July 2009, French newspaper L'Equipe announced that Bordeaux president Jean-Louis Triaud had reached an agreement with English club Manchester United for the transfer of Obertan with Triaud stating that an agreement had been reached several weeks ago and that the player had agreed contract terms. The following day, Obertan successfully passed his medical in Manchester and, on 8 July, signed his contract officially making him a Manchester United player. The transfer fee was undisclosed, but is believed to be in the region of £3 million, with Obertan joining the club on a four-year deal.
However, at the start of the 2009–10 season, Obertan suffered a setback when he suffered a spinal problem that kept him on the sidelines for a month. Following three games for the Manchester United reserve team, including a 3–0 win over Oldham Athletic on his debut, Obertan made his senior debut in the club's 2–0 away win over Barnsley in the League Cup fourth round on 27 October. He made his Premier League debut for Manchester United on 31 October, coming on as a substitute in the 2–0 win over Blackburn Rovers at Old Trafford. His Champions League debut came that same week, replacing Federico Macheda in the 82nd minute in the 3–3 home draw against CSKA Moscow on 3 November 2009. On 8 December, Obertan set up the second of Michael Owen's hat-trick in a 3–1 away victory at Wolfsburg in the Champions League, taking on 3 players before teeing Owen up for a simple tap-in. On 15 December, Obertan made his first league start for United, being replaced in the 71st minute by Danny Welbeck in a 3–0 home win over Wolves. In his first season at Manchester United, Obertan made 13 appearances in all competitions.
Obertan scored his first goal for United in a 1–0 win over Philadelphia Union on 21 July 2010 on the club's pre-season tour of North America. Just one week later Obertan was forced to miss the start of the new season as he was injured midway through the first half during United's 5–2 victory in the 2010 MLS All-Star Game. On 22 September, Obertan made his return from injury, replacing Javier Hernández in the 68th minute of United's 5–2 away League Cup win over Scunthorpe United. Obertan's first official goal for United came on 2 November, netting the second of a 3–0 away win over Bursaspor in the Champions League, this also being Obertan's first European goal. With Manchester United finished the 2010–11 season as Champions, Obertan made six appearance for the club, which
Ahead of the 2011–12 season, with his first team place increasingly limited, Newcastle United confirmed their interest in signing Obertan as a direct replacement for Joey Barton, as Manchester United planned a rebuild of their squad.
Gabriel Obertan