The 42-year-old former international defender takes over from Tim Sherwood who was sacked by Spurs at the end of last season five months after replacing Andre Villas-Boas.
Pochettino, who had managed Southampton since January last year, is the second Argentine to hold the job at Spurs after World Cup winner Ossie Ardiles who was in charge 20 years ago.
His task is to bring back the domestic and European honours Tottenham won when Ardiles and his equally revered Argentine compatriot Ricky Villa played for the north London club in the 1980s, and to secure Champions League football.
"In Mauricio I believe we have a head coach who, with his high energy, attacking football, will embrace the style of play we associate with our club," Spurs chairman Daniel Levy said.
"He has a proven ability to develop each player as an individual, whilst building great team spirit and a winning mentality. We have a talented squad that Mauricio is excited to be coaching next season."
Pochettino added: "This is a club with tremendous history and prestige and I am honoured to have been given this opportunity to be its head coach.
"There is an abundance of top-class talent at the club and I am looking forward to starting work with the squad.
Pochettino first came to the attention of England fans during the World Cup in 2002.
Then, sporting shoulder-length hair and wearing a headband, he tripped striker Michael Owen to concede a penalty in their group stage match with England in Saitama which David Beckham converted to secure a 1-0 win.
He featured 20 times for Argentina, scoring twice, after starting out with Newell's Old Boys in his homeland, making his debut aged just 16, and winning the Primera Division title in 1991 before moving to Espanyol in Spain in 1994.
He also played in France with Paris St Germain and Bordeaux before returning to Espanyol for a second spell, winning a second Copa del Rey with the club, and then retiring as a player in 2006 to begin his coaching career.
After more than 300 appearances for Espanyol he cut his managerial teeth at the Barcelona-based club but, after two decent seasons, lost his job in November 2012 with his team bottom of La Liga.
He quickly resurfaced at Southampton in January 2013 with the club 15th in the standings, finally ending the season in 14th spot.
Pochettino began to make his mark during his first and what has proved to be his only full season with the Saints, playing some bright inventive attacking football built on a nucleus of English players.
Southampton achieved some good wins last season but lost home and away against Spurs, losing 3-2 in Sherwood's first match in charge at St Mary's in December and by the same scoreline at White Hart Lane in March after leading 2-0.
Spurs, who have flattered to deceive for years in their quest for silverware and regular Champions League football, were reportedly also interested in Ajax Amsterdam coach Frank de Boer but Pochettino's attacking style should find an appreciative audience at White Hart Lane.
Even before Ardiles and Villa enjoyed success there in the early 1980s, Spurs had a rich tradition of attacking football and Pochettino's high pressing attacking style, usually based on a 4-2-3-1 formation should win over any fans who may be somewhat sceptical of his appointment after so many false dawns.
One thing that would impress them initially is if he speaks English rather than using an interpreter as he has been doing since he arrived in England nearly 18 months ago.
He has occasionally spoken to the media in English but has said that until he can express himself fully he will continue to speak in Spanish.
Ultimately Spurs fans won't mind what language he uses as long as he brings them the tangible success which has eluded them for so long.
They finished last season in sixth place and have qualified for the Europa League but while those achievements are credible, what chairman Levy and the supporters want is a trophy, a top-four finish and a place among the European elite.
Pochettino might never be regarded with the same reverence as Ardiles and Villa but if he achieves those objectives sooner rather than later, it will be a step in the right direction.
"Tottenham Hotspur has a huge following across the world and I have great admiration for the passion the fans show for this team," said Pochettino, who has brought assistant head coach Jesus Perez and first-team coach Miguel D'Agostino with him.
"We are determined to give the supporters the kind of attacking football and success that we are all looking to achieve," he added.
Born March, 2, 1972 in Murphy, Santa Fe, Argentina.
- The young centre back began his playing career with Newell's Old Boys in 1988, making his debut at the age of 16.
- Claimed his first piece of silverware in 1991 when Newell's were crowned champions of the Argentine Primera Division.
- Signed for Spanish side Espanyol in 1994, making more than 200 appearances and winning the King's Cup before joining Paris Saint Germain in 2000.
- Made his Argentina debut in 1999 and went on to earn 20 caps, playing in the 2002 World Cup, where he conceded a penalty that David Beckham scored in England's 1-0 group stage victory.
- Left PSG for Girondins Bordeaux in 2003, but struggled to settle in the south of France and rejoined Espanyol on loan during the second half of the season.
- Dubbed the "Sheriff of Murphy" because of where he grew up, Pochettino made the move to Espanyol permanent at the end of the 2003 season and went on to win a second King's Cup title in 2006 before retiring at the age of 34.
- Following his retirement, Pochettino took his coaching qualifications and had a stint as assistant manager of Espanyol's successful women's side.
- In January 2009 at the age of 36, Pochettino took charge of third-bottom Espanyol and guided them away from danger to a 10th place finish in La Liga.
- Espanyol ended in mid-table in each of the following two seasons, narrowly missing out on qualifying for the Europa League in 2011 after spending much of the campaign in the top five.
- Although his club slipped to 14th the following season, Pochettino became their fourth-longest-serving manager, having developed a reputation for bringing young players through the academy.
- At the start of the 2012-13 season, Pochettino expressed concerns about the club's financial situation, and with the team bottom of La Liga, he left by mutual consent in November 2012.
- Pochettino replaced Nigel Adkins as manager of Premier League club Southampton in January 2013, appointed by executive chairman Nicola Cortese, as the south-coast club looked to secure their top flight status after promotion the previous season from the Championship.
- Despite being relatively unknown in England, Pochettino guided the club to a 14th-place finish, enjoying wins over Manchester City and Chelsea after adopting a high-pressing, attacking style of play.
- The Argentine continued his philosophy of developing home-grown talent with England's 18-year-old left back Luke Shaw bursting on to the scene, while the likes of Adam Lallana and Jay Rodriguez also flourished under him.
- After Southampton made a solid start to the 2013-14 campaign, Cortese announced his departure from St Mary's, leading to speculation about Pochettino's future.
- But the 42-year-old, who conducts all his interviews in Spanish, said he was "100 percent committed" to the Saints and led them to eighth place - their highest ever finish in the Premier League.
- With a year left on his contract and uncertainty surrounding the future of key players, such as England internationals Shaw and Lallana, Pochettino has decided to move to north London, where he becomes the second Argentine to manage Spurs after Osvaldo Ardiles, who was in charge 20 years ago.
- Sports & Recreation
- Mauricio Pochettino
- Premier League
- Tottenham Hotspur