During his major league career, Halama played with the Houston Astros (1998), Seattle Mariners (1999–2002), Oakland Athletics (2003), Tampa Bay Devil Rays (2004), Boston Red Sox (2005), Washington Nationals (2005), and Baltimore Orioles (2006).

Halama also attended and graduated from Bishop Ford Central Catholic High School in Brooklyn, New York in 1990.

In midseason 1998, Halama was sent to Seattle along with Freddy García and Carlos Guillén in the same trade that brought Randy Johnson to Houston.

On June 5, 2008, Halama signed a minor league contract with the Cleveland Indians, and was assigned to the Triple-A Buffalo Bisons.

Halama served as the pitching coach for the York Revolution, rivals of his former team, the Lancaster Barnstormers, for the 2013 season.

Spanning a career of seven-plus seasons in the Major Leagues, Halama compiled a 53–44 record with 469 strikeouts and a 4.60 ERA in 860.1 innings pitched.