Early in his career, Markuntsov competed internationally for Russia on the junior level with Valentina Razskazova. He had the most success with Yuko Kawaguchi, competing for Japan. They teamed up in 1999 and were the first pair representing Japan to medal at an ISU Championship, which they did when they won the silver medal at the 2001 World Junior Championships. They are the 2002 and 2003 Japanese national champions. Their highest placement at a senior ISU Championship was seventh at the 2003 Four Continents. They were coached by Tamara Moskvina. They ended their partnership following the 2002–2003 season.