Waltschkou started playing tennis at the age of seven. As a junior he won the 1996 Wimbledon tournament with a final win against Ivan Ljubičić ; he finished the year on rank 7 of the junior world rankings. In the course of his career he played frequently in Challenger and Futures tournaments. Between 1998 and 2007 he was able to win 13 titles in such tournaments. He played his only final on the ATP Tour in 2002 at the Tashkent tournament . In the final he was defeated by Evgeni Kafelnikow 6: 7 and 5: 7. In early 2003 he competed with Lee Hyung-taik at the tournament in San José . They reached the final, in which they prevailed against the American duo Paul Goldstein and Robert Kendrick 7: 5, 4: 6 and 6: 3. He also celebrated great success at the tournament in Wimbledon, when he reached the semi-finals there in 2000 in singles and in 2001 in doubles.
In the Belarusian Davis Cup team Waltschkou was used between 1994 and 2008 in a total of 72 games, in which he won 43 wins.