Jim Connor will lead internal comms at Europe's largest private sector employer.
He joins the global 500,000-strong company after leading Transport for London's strategy for Olympics-time engagement of employees.
In January, Tesco issued its first profits warning in 20 years after poor trading in its home market over the Christmas and New Year period.
Since then, Tesco has struggled to gain a reputational foothold over issues such as its loss-making US business, Fresh and Easy.
Nick Howard, employee engagement and practice chair at Edelman, suggested that the company needed to take steps to make its employees act as advocates for the brand.
'When an employee goes home at the end of the day, when they are in the pub with their mates who ask "Isn't Tesco about punishing the little guy?", it is about equipping them with content so they can respond to that with pride,' said Howard.
Connor has previously worked as director of group internal comms at Centrica.
He will continue work started over the past year to bring the function up to date.
Tesco will unveil an intranet site next year. This follows the launch of the Our Tesco website, which aims to improve comms between staff in stores and depots.
Tesco's group media relations director Tom Curry said: 'We are pleased to welcome Jim Connor, who brings strong skills and experience in internal communications from previous roles at TfL and Centrica.
'Jim takes over from Greg Sage who, after five years doing a fantastic job in the role, is moving into our commercial team at Tesco as part of a general management development programme.'
Connor replaces Greg Sage, who has spent five years in the role and will move into the commercial team.
Meanwhile, it is understood that Speed Communications has been reappointed as the retained agency for Tesco Baby following a competitive review.
The agency has worked with Tesco for more than a decade. Speed's remit has included the beauty and toiletries category, although this is understood not to have been part of the review.