He was drafted by the Philadelphia Flyers in the 1993 NHL Entry Draft, Third Round, Seventy-First Overall. He has previously played for the Mighty Ducks of Anaheim, Florida Panthers, Ottawa Senators, Tampa Bay Lightning, and Philadelphia Flyers. While with the Philadelphia Flyers, Prospal suffered a fractured arm during the 1996–1997 playoffs. Prospal and another player collided during the Philadelphia Flyers practice session. During the 1997–1998 season, Prospal, who was named to the 1998 Czech Olympic Hockey Team, broke his leg while fighting for the puck with Lance Pitlick during a game with the Ottawa Senators; Prospal was unable to play in the 1998 Winter Olympics. Ironically, Prospal was traded to the Ottawa Senators a few months later. During the lockout, Prospal played for the Ceske Budejovice hockey team, leading them in scoring and helping the team reach the Czech Extraliga. At the beginning of the 2007/2008 season, while with the Tampa Bay Lightning, Prospal posted 12 goals and 10 assists making it his best career start.
On February 25, 2008 (the day before the NHL trade deadline), Prospal was dealt back to the Philadelphia Flyers for defenseman Alexandre Picard and a 2009 2nd round draft pick.
On June 18th 2008 The Tampa Bay Lightning acquired the rights to forward Vaclav Prospal in exchange for Nashville’s seventh-round pick (previously acquired), 196th overall, in the 2008 NHL Entry Draft, Executive Vice President and General Manager Jay Feaster announced. The Lightning signed Prospal shortly after which gave Philadelphia the conditional fourth-round pick in 2009 included in the offer to the rights.