Sherwood will work report to the chief strategy officer, Rebecca Morgan. At Rocket, he was executive planning director.
The Lowe chief executive, Amanda Walsh, said: "Mark is one of the most creative media planners in the UK. This appointment signals our intention to make communications planning an integral part of the planning process at Lowe and create a more future-focused offering within the agency that offers strategic, brand and communications experience.
Sherwood joined PHD's Rocket from MediaCom in 2003 following the promotion of the Rocket managing director, Mark Holden, to executive planning director at PHD.
During his time at the PHD agency he was part of the team that won a string of pitches, including the Co-operative Group, National Magazines, Mini and Tiger Beer.
He began his career as a junior media planner at Griffin Bacal in 1996, going on to join BJL Media in 1997 and MediaCom in 1999. In his four years at MediaCom, Sherwood was the lead client contact on the Masterfoods and Ikea accounts.
Lowe joins Bartle Bogle Hegarty and TBWA in offering comms planning to its clients. In May, CHI & Partners appointed Enyi Nwosu to work alongside Tim Allnutt, the former managing partner at CHI's Naked Inside joint venture, on a hybrid communications and account planning initiative, branded "ideas planning".