He is married to Yvette Nagel, daughter of former Leefbaar Nederland political party president and politician Jan Nagel.
For many years he was the chief editor of the Inside Chess magazine, which however later became an Internet-only magazine and later just a Column at the Chesscafe website.
In the year 2001 (?), Seirawan released a plan to reunite the chess world, which at that time had two world champions: Ruslan Ponomariov had gained the title under the auspices of FIDE, while Vladimir Kramnik had beaten Garry Kasparov to take the Einstein title. It called for one match between Ponomariov and Kasparov (the world number one), and another between Kramnik and the winner of the 2002 Einstein tournament in Dortmund (who turned out to be Péter Lékó). The winners of these matches would then play each other to become undisputed World Champion. This plan was signed by all parties on May 6, 2002, in the so called "Prague Agreement". As of November 2004, only the Kramnik-Leko match has taken place (the match was drawn, with Kramnik retaining his title); the Kasparov-Ponomariov match was cancelled in 2003, and the future of the reunification plan remains uncertain.
Following a series of events Seirawan participated in China during September 2003, there were reports that he would be retiring as a professional player. Although he subsequently played two games in the Dutch team championship in May 2004, these are, as of November 2004, the only professional games he has played since then.