The Argentinian goalkeeper was signed on a three-year deal as a free transfer having been let go by Serie A side Sampdoria.
Speaking to ManUtd.com about his move, Romero insisted he was itching to get started at his new club.
“I am absolutely delighted to join Manchester United,” he said.
“To play for the biggest club in the world is a dream come true for me. Louis van Gaal is a fantastic manager and I cannot wait to get started on this new and exciting challenge in my career.”
Louis van Gaal is equally as happy to have signed Romero. He said: “Sergio is a very talented goalkeeper. He was a young keeper during my time at AZ Alkmaar and I am delighted he is joining Manchester United.
“He had a fantastic World Cup last summer in Brazil, although that is something I have put to the back of my mind! He will be a great addition to the team and I am looking forward to working with him once again.”
With all due respect to Sampdoria, United are a far bigger club and this is a massive step for Romero in his career. Here’s hoping he can do well, whatever his role may be in the upcoming season.