Sternheimer joins the law firm as a partner and will lead their newly opened Swiss office, based in the Olympic capital Lausanne, where CAS is also located.

Morgan Sports Law said the office, headed by Sternheimer, will be an important geographical and strategic development in growing their international footprint.

Sternheimer leaves CAS after 10 years, having initially joined as counsel.

He later become the managing counsel and head of arbitration, before becoming the deputy secretary general.

During his tenure at CAS, Sternheimer managed more than 940 CAS arbitrations covering all subject matters, including contractual, regulatory, governance and disciplinary disputes, with the latter including anti-doping, match-fixing and financial fair play.

More than 700 of these cases related to football.

Disputes also involved American football, aquabike, aquatics, archery, athletics, badminton, basketball, biathlon, bowling, boxing, canoeing, chess, cycling, draughts, equestrian, skating and gymnastics.

He also managed cases involving handball, judo, kickboxing, martial arts, powerboating, motorcycling, powerlifting, shooting, skiing, squash, taekwondo, tennis, volleyball, weightlifting and wrestling.

Sternheimer also managed CAS ad-hoc divisions at the Rio 2016 and Pyeongchang 2018 Olympic Games.

"I am extremely excited to start the next chapter of my career at Morgan Sports Law," Sternheimer said.

"I have been very fortunate to work at the CAS, the ultimate arbitral body for sports disputes, for a decade and joining Morgan Sports Law was a natural next step for me to take.

"Morgan Sports Law is a truly international law firm which, within a short period of time, has become known globally for its expertise in sport dispute resolution and anti-doping.

"I look forward to spearheading the Lausanne office and drawing on my expertise to support clients, and act in cases before the CAS and other tribunals across the world."

Morgan Sports Law was founded in 2013 by London-based lawyer Mike Morgan and has since been involved in numerous high profile cases.

They worked on British cyclist Chris Froome's successful defence, which saw the four-time Tour de France winner cleared by the International Cycling Union after a positive test for salbutamol.

The firm successfully defended British cyclist Lizzie Deignan when she avoided a four-year ban in 2016 following three missed drugs tests within a 12-month period.

Other recent clients include Russian tennis player Maria Sharapova, French footballer Mamadou Sakho, Spanish and South African cyclists Sergio Henao and Daryl Impey, Jamaican sprinter Veronica Campbell-Brown and Croatian tennis player Marin Čilić.

They also supported boxer Tyson Fury after he was cleared to compete again despite accepting a two-year drugs ban from UK Anti-Doping.

In addition they have been hired by Russian athletes and the country's National Olympic Committee during the doping scandal there.

"We're very pleased to welcome William Sternheimer to our growing team at Morgan Sports Law," Morgan said.

"William brings a breadth of experience in international sports arbitration that is unmatched.

"William's arrival fits perfectly with our plans to keep expanding our capabilities in sports arbitrations and to keep growing our international footprint."

Morgan Sports Law said their new Swiss office "cements the firm's reputation for having the largest dedicated sports dispute resolution team in Europe".