She will guide the network's programming as CBS tries to exploit its costly acquisition of NFL broadcasts and the addition of a second night of its long-running Sunday news magazine, 60 Minutes.
Tellem, now in charge of CBS Productions and CBS Entertainment's business affairs unit, will oversee CBS Entertainment's operations for prime time, daytime, late night and Saturday morning.
She will be getting help from her predecessor, CBS Television President and Chief Executive Officer Leslie Moonves, who was promoted in April.
Although other entertainment division departments will report to Tellem, the program planning and scheduling unit will remain under the control of Moonves as he stays "actively involved" at CBS Entertainment, the network said Monday.
The intent, Moonves said, is to maximize the coordination of entertainment, news and sports programming and expand the unit's focus "at a time when news and sports are playing increasingly important roles on our schedule."
Moonves and Tellem worked together at Warner Bros. Television, where he was president and she was an executive vice president, and at Lorimar Television before it was acquired by Warner. She joined CBS in 1997.
Tellem is the second woman to serve as programming chief at one of the three major broadcast networks. ABC Entertainment President Jamie Tarses was appointed in 1996.
Written By Lynn Elber, AP Television Writer