Edelman has worked in more than 30 countries across Africa in recent years. Revenue growth in in continent was 21.4 per cent in 2019, with headcount up from 51 to 76.
Williams - who moved from UK CEO to EMEA boss last year - said: "Our strategy is to be pan Africa so naturally you'll expect us to look at Nigeria at some point. I think that growth market, the energy and dynamism and opportunity in Africa, is really quite profound.
"There are big brands there, there are large consumer markets, and there are clients that want to do innovative creative work. So for us, Africa under [Edelman Africa CEO] Jordan Rittenberry presents a real opportunity."
Williams spoke to PRWeek about Edelman's financial results in EMEA, where revenue in 2019 rose 2.4 per cent to $183.7m.
Among the fastest growing offices were in Belgium, the Netherlands and Ireland, which all experienced growth of about 20 per cent. South Africa was slightly ahead at +21 per cent.
Slower markets included France, which grew between one and two per cent. Revenue across Continental Europe rose slightly, from €69.9m to €70.2m.
Last year Edelman moved to having a single P&L in the UK, and Williams said: "We're a portfolio business, and if we have one P&L in the UK, at the very least I want a mindset of one P&L across EMEA, even if it's not the application of it.
"Therefore, there's going to be times in which certain markets, due to local market dynamics, don't perform as well as others in relative terms. But if you're running a portfolio business that's fine because you have your risks spread across multiple markets."
Recent months have seen senior London execs given more responsibility over the wider EMEA region, which employs more than 1,200 people. For example, Ruth Warder, chief client officer at Edelman UK, also oversees the brand work across EMEA, and chief digital officer Toby Gunton is to lead digital in the region.
Williams said he wanted to "try and take the lessons and successes from London and apply those successes regionally".
"That means trying to unlock the power of the collective. It means putting together multi-disciplinary teams that cross borders, whether they are specialist skills, sector knowledge... and now trying to implement that blueprint from a management perspective more generally across EMEA."
Revenue in the Middle East fell from £16.7m to £14.1m in 2019. On trading in the region, Williams said: “In the last year we’ve focused on consolidating and streamlining our offer. This included moving away from offering experiential as a service, which impacted our revenue in the short-term. However, we continue to focus growing our business in the Middle East across corporate reputation and brand.”