Sheikh (formerly Salmon) will report to group chief commercial officer Morten Lundal and will be responsible for the group's brand framework, creative strategy and brand identity.
Sheikh is a high-profile figure within the marketing community.
She stepped down from her most recent role as group strategy, marketing and customer director at RSA in May after four years at the insurance giant. Previously, Sheikh held senior strategic and marketing roles with Prudential, Centrica, ITV and British Gas.
Lundal said: "I look forward to working with her to enhance further our strong global brand, making it even more relevant, personal and engaging for our customers."
The last person to hold the role of group brand director at Vodafone was David Wheldon, who left the mobile giant in 2010.
Its marketing operations have subsequently undertaken a restructure, and the role of group brand director has since been vacant.