The Argentine addressed the media on Friday, November 13, following confirmation of his appointment as Manchester United manager after Michael Carrick's departure.
Pochettino, 54, had signed a contract extension with US Soccer in August that was expected to keep him in charge of the national team until 2030. However, the opportunity to manage Manchester United proved difficult to turn down.
Speaking during his farewell, the former Tottenham Hotspur, Chelsea and Paris Saint-Germain manager expressed gratitude to the players, coaching staff and supporters for their backing during his two-year spell.
He said: "We learned a lot from you all, from this amazing country. I think this was one of the most difficult decisions of my career."
Pochettino admitted that leaving the project was particularly painful because of the strong relationship he had developed with the team and the federation.
He also explained that discussions over the Manchester United opportunity developed quickly, with an agreement reached between the two football organisations before he informed the players.
According to Pochettino, the players were supportive after he communicated his decision to them.
Pochettino to oversee final USMNT matches
Despite his departure, Pochettino will remain with the United States for their two CONCACAF Nations League quarter-final fixtures against Haiti before beginning his new assignment in England.
He stressed that the agreement between US Soccer and Manchester United would allow him to fulfil his remaining commitments to the national team.
During his time in charge, Pochettino helped the United States reach the last 16 of the 2026 FIFA World Cup. His record across 35 matches stood at 21 victories, 12 defeats and two draws.
US Soccer is now expected to begin the process of finding a successor after the current international camp.
A new challenge at Manchester United
Pochettino's appointment brings an end to his latest international management experience and gives him another opportunity to make an impact in the Premier League.
The Argentine previously managed Tottenham and Chelsea in England, but his move to Old Trafford represents a fresh challenge at one of the country's most prominent clubs.
He acknowledged that opportunities to manage a club of Manchester United's stature do not come around frequently, explaining why he felt unable to reject the offer despite his commitment to the United States project.