Barry will take up his new role at CHI in July, where he will be reunited with Lowe's former creative director, Charles Inge. He will have a floating role across all of the agency's accounts.
Barry will not be directly replaced at Lowe, where his partner and fellow creative director, Damon Collins, will now take sole control of the agency's creative department.
Barry and Collins took responsibility for running Lowe's creative department last September, ending months of speculation about the creative leadership.
The creative helm had been caretaken by the chairman, Paul Weinberger for the 14 months after Inge's departure. The agency had been in advanced talks with an external candidate, but opted to promote the internal senior team instead.
Inge hired Barry and Collins in 2000. In recent years, Barry has created high-profile campaigns including Heineken's "blackmail" spot, Reebok's "sofa" ad (which he co-wrote with Vince Squibb), and the launch campaign for Tesco's Cherokee range of casual clothes.
Before working for Lowe, Barry worked at Wieden & Kennedy, where he worked on Nike. He has also worked at M&C Saatchi and Simons Palmer Denton Clemmow Johnson.
"Tony has always produced award-winning work, and is still doing so. That's all you can ask," Inge commented. "We've got some big creative opportunities here at CHI, and Tony will get a chance to write and get involved in some fantastic ads. He'll be working across all our accounts."
Lowe's incoming chief executive, Matthew Bull, said: "We wish Tony well. He's a hell of a talented guy and he'll do a fantastic job at CHI, but Damon is a very talented, ambitious man and we're 100 per cent behind him."
Barry added: "CHI are incredibly bright, good people who care, and I just wanted to be a part of that."