From TheChels.info - The Chelsea Football Club Wiki
Frank Arnesen (born 30 September 1956) was Sporting Director at Chelsea from 2009 until 2011, having been hired in the summer of 2005 as Head of Youth Development and Scouting.
Frank was a notable player, spending the majority of his career playing in the Netherlands, spending six years at Ajax Amsterdam. He won the 1988 European Cup with rivals PSV Eindhoven, having taken in spells at Valencia and Anderlecht between clubs. An attacking midfielder, he also made 52 appearances for Denmark, scoring 14 goals and playing in the European Championships of 1984 and 1988.
Three years after retiring, Arnesen became Assistant Manager at PSV, working under Bobby Robson. The Englishman left the club a year later to work at Sporting Lisbon, but in 1994 Frank was promoted to General Manager in Eindhoven, a post he held for ten years.
He was widely credited with 'discovering' an array of world-class talents, most notably Ronaldo, Ruud van Nistelrooy, and Arjen Robben, who would later sign for Chelsea. Overseeing a worldwide scouting network, the Dane was famed for his dossiers and files regarding hundreds, if not thousands of footballers worldwide.
He joined Tottenham Hotspur in May 2004 as Director of Football, but struggled to co-exist with manager Jacques Santini. The Frenchman left early in their relationship, and was replaced by Martin Jol, who Arnesen had hired as Assistant Manager.
Whilst working at Tottenham, Arnesen was courted by staff at Stamford Bridge, eager to bring him to Chelsea. The situation caused some controversy - Tottenham believed that the approach made by scout Piet de Visser was illegal, and indeed, imcumbent manager José Mourinho felt the proposed move would have undermined his authority.
Nonetheless, in June 2005 a compensation package of £5m was agreed and Arnesen began a new role at Chelsea as Head of Youth Development and Scouting. Working almost exclusively with the academy, his arrival was part of the overhaul of the club's youth ranks which had begun the previous year.
Despite the remit of his role, he was instrumental in the arrivals of John Obi Mikel and Salomon Kalou, and yet received great criticism from supporters who believed he was being paid too much without providing results. Mourinho also criticised the Dane before his departure in 2007, claiming that the club's youngsters were not sufficiently talented to make the grade.
In the summer of 2009, Arnesen was promoted to the position of Sporting Director, a move which added greater first team responsibilities to his role whilst retaining his previous position in the academy. Chelsea saw increased success at youth level under Arnesen, winning the FA Youth Cup in 2010, the first time since 1961. Though no youth product had established themselves in the first team at the time of the Dane's departure in 2011, the academy was left with several highly promising prospects, and Josh McEachran had made 17 appearances during the 2010-11 season.
Having announced in November 2010 that he would be leaving Chelsea at the end of the 2010-11 season, it was confirmed in February 2011 that Arnesen would be joining Hamburg in the summer. Upon his arrival in Germany, one of the Dane's first actions was to sign defender Michael Mancienne from Chelsea, with Gökhan Töre and Jacopo Sala signing a short time later, and Jeffrey Bruma joining on loan.