Webb was an MP between 1997 and 2015, and spent the whole of the previous coalition Government between 2010 and 2015 as the minister of state for pensions.
Prior to Westminster he was a professor of social policy at Bath University, and before that worked for think-tank the Institute for Fiscal Studies.
In what is a newly created role, Webb will "oversee the public relations and public affairs activity for Royal London and act as a key spokesperson for the group", a company press release says. It goes on to say that under parliamentary rules, Webb is barred from "any direct lobbying activity for the first two years of his appointment".
Webb takes up the role on 9 November. A spokesman for Royal London said that this was to fulfil a six-month post-election embargo on certain appointments stipulated by the Government's Advisory Committee on Business Appointments, which the spokesman said had approved Webb's appointment.
His appointment comes at a time of change for the Royal London's brands – it is currently moving all of its UK businesses, which include Scottish Life and RLCIS, together under a new version of the Royal London brand, although its Ascentric brand will remain independent.
Phil Loney, Royal London's chief executive, said: "Having debated public policy issues with Steve during his tenure as pensions minister I know that he shares Royal London's values and is a supporter of our customer-owned business model."
Webb said: "Having been involved in designing policy in areas such as automatic enrolment I am looking forward to seeing how it is implemented on the front line. As someone who has always wanted a better deal for pension savers, the customer-focused ethos of Royal London is a perfect fit with my priorities and I am greatly looking forward to this opportunity."