Bradley, who was Tesco’s longest-serving marketer when she left in 2013 in the midst of a restructure, will advise the beer group on its marketing strategy when she joins as an independent non-executive later this year.
The Burton-upon-Trent brewer, which owns brands including the eponymous Marston’s, Banks’s, Wychwood and Brakspear, also operates 2,150 pubs and bars across the UK.
Marston’s has also appointed Catherine Glickman as a non-executive director.
Roger Devlin, Marston’s chairman, said: "I am delighted to welcome both Carolyn and Catherine to Marston’s. They will bring valuable marketing and human resources experiences from different businesses and both have had successful careers in a leading retail consumer facing business.
"These skills will be of great benefit to Marston's as we seek to expand our own business in branded pub-restaurants and brewing.’’
Bradley joined Tesco in 1986, becoming loyalty director in 1992. Her tenure included roles as chief operating office for Tesco.com from 2000 to 2003, followed by commercial director for Tesco Stores, until she become UK marketing director in 2008.
She was promoted to group brand director in 2012, working in a newly created group marketing team set up by then deputy chief executive and CMO Tim Mason.