A native of Sapporo, Hokkaido and graduate of Aoyama Gakuin University, he was elected to the House of Representatives for the first time in 2003 after unsuccessful runs in 1996 and 2000.

In 2010, Matsuki was expelled from the Democratic Party of Japan for voting in favor of a no-confidence motion in then-Prime Minister Naoto Kan.

In 2014 he ran as a candidate of the Japan Innovation Party and gained a Diet seat through the Hokkaido proportional representation block.

In 2021 he won the Hokkaido 2nd district as a member of the Constitutional Democratic Party after the LDP incumbent resigned over corruption accusations.

Matsuki is affiliated to the openly revisionist organization Nippon Kaigi.