Robert F. Hughes

 was the animation director for Phineas and Ferb in Season 1, a director for the show starting with Season 2 and as of Season 4, the show's producer.

Episodes he directed
He was also one of the directors of "Phineas and Ferb The Movie: Across the 2nd Dimension".

Episodes he wrote and storyboarded

 * "Phineas and Ferb Summer Belongs to You!"
 * "Rollercoaster: The Musical!"

He also wrote additional material for "Phineas and Ferb The Movie: Across the 2nd Dimension".