Miura, who joined Oliveirense on loan from Yokohama FC earlier this year, came on in the 90th minute of a 4-1 win at Academico de Viseu.
According to a report on the Portuguese league's website, Miura's appearance made him "the oldest footballer ever to play in Portuguese football, with 56 years, one month and 24 days".
Miura, who is in his 38th season of professional soccer, has played for a string of clubs across the world including Palmeiras, Genoa, Dinamo Zagreb and Vissel Kobe.
Portugal is the sixth country Miura, dubbed "King Kazu" by fans, has played in after starting his globe-trotting career with a spell at Brazil's Santos in 1986.
He played 89 times for Japan, winning the Asian Cup in 1992, and is the country's second-highest all-time scorer with 55 goals. His last international match was in 2000.
