Joseph, who left Sport England in January after five years, also runs a consultancy business, Tanya Joseph Consulting, and holds non-executive roles with Time to Change, the Fawcett Society and the Thomson Foundation.
At The Pool she will work with chief executive Sam Baker, broadcast director Lauren Laverne and chief commercial officer Jo Morrell to develop the brand’s offering.
The Pool has also made a pair of commercial appointments. Sam Cocker joins from Mumsnet as partnership director with a particular focus on tech, finance and food, while Melanie Hearn joins from Grazia to lead partnerships with fashion brands.
Joseph said: "The Pool is a brilliant platform for powerful female voices in the UK and increasingly internationally. The business is at a very exciting point in its evolution and I am thrilled to a part of such an innovative brand in the media space. I am particularly excited to be joining a team of strong women leaders."
"This girl can", launched in January 2015, was designed to encourage more women to get involved in sport. It has been credited with getting at least 2.8 million women to do more sport.
The Pool was launched by Baker and Laverne in 2015, and struck a content marketing partnership with DigitasLBi later that year.
Baker added: "Tanya is a fantastic and inspirational figure and we are so excited to have her on board. We have just celebrated our second anniversary with a Webby and are proud to be recognised as a unique digital platform for women. These new appointments reflect just how far we have come in two years."