Joseph, a former press secretary to ex-Labour Prime Minister Tony Blair, will be tasked with helping the brand address any social and national issues it wants to hone in on, beginning with housing.
Giving a flavour of what's in store from Joseph in the purpose-focused role, Nationwide's chief executive Joe Garner said: "Her breadth of experience will support Nationwide’s ambition and contribute to our core purpose of ‘building society, nationwide’, engaging and collaborating with a wide range of policy makers and influencers."
The marketer has held a series of senior comms roles consulting brands like Mars, Heinz and Tesco, and working in-house. From 2012 until 2017 she served as director of business partnerships at Sport England, where she was credited with being the mastermind behind Sport England's Cannes Lion-wining 'This Girl Can' campaign. Created by FCB Inferno, the initiative claimed to have inspired 2.8 million UK women and girls to get active in the year after its 2015 launch.
In 2017, Joseph was appointed to chair startup publisher The Pool, tasked with applying her marketing flair to help the women's title become a profit-pushing, agenda-setting, online media giant.
She is also vice-chair of the Fawcett Society and a trustee of the Thomson Foundation – a charity dedicated to raising standards of journalism in developing countries.
The marketer said she was "particularly excited" about supporting Nationwide's focus on housing.
"As an institution with a history of more than 130 years it is uniquely placed to take a leadership role in addressing this long-term social issue," she added.
Since 2016, Nationwide has sought to portray itself as a brand that has a supportive voice for what matters in society, using the tones and stories of everyday people to convey its 'Voices Nationwide' positioning.
Its most recent campaign featured two singing sisters Flo and Joan relaying the importance of loyalty and close family relationships.