Derby have appointed as the club's new president and chief executive officer.
With Tom Glick's departure to Premier League champions Manchester City, Rush will take up the role as the American's successor on January 1, 2013.
Rush, who played rugby union for Saracens, is currently president of the Wasserman Media Group's football division, based in London, and has 15 years experience of working in the sports business industry.
Speaking about the appointment, Derby chairman Andy Appleby said: "Sam's experiences at the forefront of the sports business industry, plus his global football connections, mean he will come to Derby well prepared to tackle the next stage of the club's development.
"We have been looking for a strong candidate who could work effectively with the ownership group, plus the strong management and executive team already in place at Pride Park. Sam fits the description perfectly and I am delighted that somebody of his calibre has agreed to join us."
Rush trained as a lawyer and worked for distinguished legal firms Bird & Bird and SJ Berwin before moving to Clear Channel Entertainment.
He then worked for sports marketing agency SFX Sports, before it was acquired by WMG, firstly as chief operating officer and latterly as president of football.
Rush has played a crucial role in the expansion of WMG as a global force in sports and entertainment.
According to the WMG website, his current role involves overseeing the management of "more than 400 of the sport's biggest stars from the US, UK and across Europe".
Indeed, WMG include Mark Cavendish and Amir Khan among their clients.
Commenting on joining Derby, Rush said: "It is an honour to be offered the chance to join Derby County.
"Within the UK sports business industry, Derby are rightly seen as an innovative club, and I look forward to delivering some of the exciting plans already in place, as well as bringing some of my own ideas to Pride Park."
Rush is also a director and current treasurer of the British Association for Sport and Law, a director of the Association of Football Agents and was appointed by Sport England in 2005 as a non-executive director of the Amateur Boxing Association.