In 1987-88, Walz played his first major junior game with the WHL's Prince Albert Raiders, scoring a goal and an assist. The following season, he joined the Lehtbridge Hurricanes and had 75 assists and 104 points as a WHL rookie. In 1989-90, he scored 54 goals and 140 points and was named a WHL East 1st Team All-Star. In the playoffs, he scored a league-best 24 assists and 37 points in 19 games. The Boston Bruins selected Walz with their 3rd-round pick in the 1989 NHL Entry Draft. During his rookie season with the Bruins, he scored eight goals and eight assists and after 15 games in 1991-92, he was traded with Garry Galley and a 3rd-round draft pick to the Philadelphia Flyers for Gord Murphy, Brian Dobbin, and a 3rd-round draft pick. He played just two games with the Flyers before the close of the season. On August 26, 1993, Walz signed as a free agent with the Calgary Flames. That year, he scored 38 points in 53 games as the Flames won the Pacific Division title.



In the shortened 1994-95 campaign, he played 39 games with the Flames as they repeated as Pacific Division champions. On September 6, 1995, Walz signed as a free agent with the Detroit Red Wings. That season, he played two games at the NHL level. Frustrated at his lack of NHL success, he opted to play two seasons with Lugano in the Swiss Elite League, winning the league title in 1998. After finding new confidence in his game, Walz returned to the NHL with the expansion Minnesota Wild in 2000-01, playing all 82 games, scoring 18 goals and assisting on 12 others. Over the next three seasons Walz continued be an on ice leader with the Wild and was instrumental in the team's playoff success in 2003. Walz won a gold medal with Canada at the 1990 World Junior Championships. Just over eleven years later, he represented the national team at the 2001 World Championships.