Greenhalgh, whose work includes Bacardi "platform" and this summer's Wimbledon commercial for the BBC, joins Home Corp along with his long-standing producer, Genevieve Simmers.
However, he remains with Believe Media for music videos representation.
By moving to Home Corp, the prolific director is returning to the company where he began his career. Greenhalgh began directing commercials at the Brave Film Company in 1995.
Brave was renamed Home Corp after the joint managing directors, Emily Bliss and Michelle Stapleton, decided to part company.
"As the industry seems to change on a daily basis, I decided to move on to a place I felt I already knew," Greenhalgh said.
"I had a great relationship with Emily at Brave and I'm excited to be returning home for a reunion."
After he left Brave, Greenhalgh went on to direct at Godman and then Exposure Films. His reel also includes commercials for Reebok, Adidas and Citroen.
At Home Corp, he joins a roster that includes Lucy Blakstad, Jason Smith, Sara Dunlop and Sue Worthy.
Commenting on Greenhalgh's appointment, Bliss, the managing director of Home Corp, said: "Howard has always been a unique and original talent and we are very proud and excited to have the chance to work with him again."