Emanuel Lasker was the second official world champion and managed to hold the title for 27 years. His reign initiated in 1894 and lasted ’til 1921, being the longest one of any world chess champion. He played for five decades.
Lasker was the one that managed to defeat the first official world champion Wilhelm Steinitz in 1894, defending his title five times against different world-class contenders, such as Frank Marshall, Siegbert TARRASCH, David Janowsky, and Carl Schlechter.
Back in 1921, Lasker lost the title to Capablanca but kept playing at his highest level. He placed third in 1935 that took place in the Moscow tournament, at 66 years old.