McPhail joins the agency from Hill+Knowlton Strategies, where she worked for nearly eight years as head of its beauty and grooming division, leading a team of 12 on clients including Gillette, Braun and Shockwaves.
Prior to that, McPhail worked alongside Aisle 8 co-founder Lauren Stevenson in the consumer team at Ketchum London.
McPhail, who returns to the industry after a career break to have children, will help to grow Aisle 8's consumer division, which services clients including Ferrari and Karen Millen.
The agency has also sealed the deal on the UK PR account for luxury online children’s fashion store Melijoe, founded in Paris. It will manage all UK PR and comms for the brand, including founder profiling, collaborations, product and brand news placement.
Stevenson said McPhail's appointment was "a strategic hire that reflects our desire to strengthen the Aisle 8 offer in the consumer and lifestyle sector".