Willem Heemskerk is sinds 1992 advocaat bij Pels Rijcken. Hij heeft zich ontwikkeld tot één van de meest ervaren litigators van Nederland. Willem behandelt complexe civielrechtelijke geschillen voor veelal grote (internationale) ondernemingen.
Willem studeerde Nederlands recht aan de Universiteit Leiden. Op het terrein van het burgerlijk procesrecht wordt Willem als groot specialist beschouwd: hij heeft veel publicaties op zijn naam staan, is vice-voorzitter van de Adviescommissie voor burgerlijk procesrecht en treedt geregeld in buitenlandse procedures op als expert. In de Chambers Global en de Chambers Europe Practice Guide wordt Willem gerankt in Band 1 voor Dispute Resolution. Eind 2018 is Willem na een door de VIA georganiseerde verkiezing uitgeroepen tot 'Beste Procesadvocaat van Nederland'.
- Clients highlight his "great international experiences and extensive knowledge of jurisprudence," while adding that "he is very pleasant to work with and makes you feel at ease." Others regard him as an excellent lawyer whose "strategic skills are second to none.", Chambers Global en Chambers Europe 2019
- "Sources tout him as a 'very experienced litigator' who has 'a broad view' and 'in-depth knowledge' of the way the law is applied.", Chambers Global 2018
- "It is jointly led by real litigator Willem Heemskerk, who is committed to his clients and always able to think outside the box, and the sharp Hans van Wijk, who is a specialist in Supreme Court matters and very thorough in his approach.", Legal 500 2018
- "He is a real litigator: resolute and committed to his clients. With a flexible mind, he is able to think outside the box and come up with solutions, no matter how complicated the question he's dealing with.", Chambers Global and Chambers Europe 2017
- "Well-respected firm Pels Rijcken & Droogleever Fortuijn NV is ahead of the curve; its team comprises experienced, smart and very responsive litigators, including the down-to-earth Willem Heemskerk, [...].", Legal 500 2017
- “Willem Heemskerk is appreciated by clients: ‘He is really experienced, pleasant to work with and no-nonsense’.", Chambers Global en Chambers Europe 2016
- "Willem Heemskerk is 'always able to think outside the box'.", Legal 500 2016
- "He is an outstanding lawyer. He deals with complicated cases in a timely manner.", Chambers Global en Chambers Europe 2015
- "The 'pleasant' and 'hardworking' Willem Heemskerk has 'very good negotiation skills'.", Legal 500 2015
- "He is very fast and thorough, and good at addressing all the sides of complicated matters.", Chambers Global en Chambers Europe 2014
- "Within five minutes he can find a way to tackle any problem. He’s good at his work and also good to work with.", Chambers Global en Chambers Europe 2013