Possible Clues:

• Co-star of 6-Down in 1970s TV
• He voiced the curmudgeonly homeowner in "Up"
• Only actor to win a comedy and drama Emmy for the same character
• ''Up'' voice actor
• Moore/Knight co-star
• Long-time Moore costar
• "Lou Grant" star Ed
• Moore's sitcom boss
• Ed with many Emmys
• Capt. Davies's portrayer in 'Roots'