Dobler was drafted in the fifth round out of the University of Wyoming in the 1972 NFL Draft by the St. Louis Cardinals. He played right offensive guard for the Cardinals from 1972-77, next to Hall-of-Famer Dan Dierdorf at right tackle. In those years, the Cardinals had solid offensive lines, especially for pass blocking; they allowed just eight sacks in all of 1975, then a record (though helped by quick releases from quarterback Jim Hart). Dobler was an important cog of this success, making three consecutive Pro Bowl appearances from 1975-77.
Dobler quickly developed a reputation as a nasty player, and he did little to tone down that image. On the contrary, he seemed to revel in it, probably believing that this would intimidate some defensive players, as indicated by the following quote: “I see defensive linemen jump to knock a pass down. When that happened near me, I’d smack ’em in the solar plexus, and that got their hands down real quick.” As sportswriter Paul Zimmerman said: “Conrad Dobler was mean dirty. He tried to hurt people in a bad way…he made teams that he played on better. He played hurt, didn’t complain, but he was a filthy, filthy player.” He made the cover of Sports Illustrated, who heralded Dobler as “Pro Football’s Dirtiest Player”.[