Neckář was a second round choice for the Ottawa Senators, 29th overall in the 1994 NHL Entry Draft. His other former teams include New York Rangers, Phoenix Coyotes, Tampa Bay Lightning and the Nashville Predators. During the 2005-2006 season, Neckář was playing in Sweden for Elitserien team Södertälje SK.
In his entire NHL career, Neckář played a total of 510 regular season games; scoring 12 goals and assisting on 41 others for a total of 53 points. He also played 29 playoff games, scoring 3 assists for 3 points.