Phillip started his senior career in the Ugandan leading club Villa SC having won five national Championships in a row. In December 2003 he moved to Europe, to play in Serbia in the Serbian First League (2nd Serbian tier). That club is known for bringing many Ugandan players to Europe, but after ending that season, Ssozi was back to Africa, this time to play in Rwandan leading club APR FC from the country's capital Kigali. There he won that year, 2005, the Rwandan Premier League. After that season, he was back to Uganda where he first played in Kampala's Victor FC and, since 2007 is playing in another capital's club, the Express Red Eagles.