Final answer:
Theodore Roosevelt hired Louis C. Tiffany for the renovation of the White House during his presidency.
Step-by-step explanation:
The president who hired Louis C. Tiffany—first design director of Tiffany and Co.—for a massive renovation of the White House and its private chambers was Theodore Roosevelt. This renovation included updates and enhancements in style and function, reflecting Roosevelt's progressive vision for the presidency and the United States. Tiffany, known for his beautiful stained glass work and innovative designs, was responsible for bringing a new aesthetic to the White House during this period.