Sham has been with the Cowboys since 1976, when he was hired to be their color analyst alongside play-by-play man Verne Lundquist.
Sham also held the position of Sports Director at former Cowboys Radio Network flagship station 1080 AM KRLD between 1976 and 1981.
When Lundquist left for CBS in 1984, Sham became the lead play-by-play man, a position he has held ever since (save for three seasons in the mid-1990s).
In 2003, Sham wrote Dallas Cowboys: Colorful Tales of America's Greatest Teams (ISBN 0762727594).
The 2009 season marked Sham's 30th year with the organization; the longest of any broadcaster with the team, albeit not consecutive due to his three-year absence from the club from 1995 to 1997.