Werenka played college hockey for the Northern Michigan University Wildcats, with whom he won the 1991 NCAA hockey title. In 1986-87, he enrolled at Northern Michigan University and scored eight points as a WCHA freshman. The following season, he improved to 30 points. In 1988-89, he scored 20 points in 28 games and helped his school win a WCHA championship. After scoring seven points in eight games the following season, he then scored 20 goals and 63 points as a college senior in 1990-91. He was named both a WCHA First Team All-Star and a NCAA West First Team All-American that year. At the NCAA championships, he was named a tournament All-Star.
Brad Werenka was selected 42nd overall in the 1987 NHL Entry Draft by the Edmonton Oilers. During the 1992-93 season, he played his first 27 games at the NHL level and scored five goals and nine points. In 1993-94, he was traded on March 21 to the Quebec Nordiques for Steve Passmore.
On July 20, 1995, Werenka signed as a free agent with the Chicago Blackhawks. That season, he played nine games for the Blackhawks. On July 31, 1997, he signed as a free agent with the Pittsburgh Penguins. He joined the NHL ranks full time that season and helped the team win the Northeast Division title, scoring 18 points in 71 games on the blueline.
In 1991-92, he turned pro with the AHL's Cape Breton Oilers and scored 27 points in 66 games. In 1992-93, he played four regular-season games with the AHL Oilers.
In 1995-96, Brad scored 15 goals and 57 points in 73 games with the IHL's Indianapolis Ice. He then scored four points in five playoff games. In 1996-97, he played all 82 games and scored 20 goals and 76 points on the blueline. He was named a First Team All-Star and was presented both the Governor's Trophy (top defenceman) and Ironman Award at season's end. In the playoffs, he scored five points in four games.
In 1992-93, Werenka scored ten points in 18 games with the Canadian national team. He then played eight games for his country at the 1994 Olympics in Lillehammer. He scored four points and helped his country win the silver medal.