Mlynarik is originally from Czechoslovakia, born in Děčín, a town now part of the Czech Republic. Based in Vienna, he began competing professionally from 1998. He made his only main draw appearance on the ATP Tour at his home event, the 2000 CA-TennisTrophy, where he was beaten the first round by eighth seed Cedric Pioline. At Challenger level he won two titles, the singles at Lübeck in 2001 and the doubles at Canberra in 2004. He competed in the qualifying draws of all four Grand Slam tournaments.
