The 6-foot-8 Pope played the last three seasons for Kansas City and follows former Chiefs Coach Todd Haley to Pittsburgh. Haley is the Steelers' new offensive coordinator.
Financial details of the one-year contract were not disclosed.
The Steelers were in need of a backup tight end to play behind Health Miller after Wesleye Sanders was suspended for the first four games of the 2012 season for using performance-enhancing drugs, the Pittsburgh Post-Gazette said.
Last season, Pope started 10 games for Kansas City and appeared in all 16 games, finishing with a career-high 24 catches for 247 yards and one touchdown.
He was selected by Arizona out of Georgia in the third round of the 2006 NFL Draft and played three seasons for the Cardinals.