Sergii has been in project management since 2008, now certified as IPMA (Level A) and licensed as BREEAM International Assessor. He established KEY Group in 2011 as a response to the engineering needs of big Ukrainian companies. NEPTUNE Grain terminal for Cargill, projects with international funds and organizations in Ukraine are among the jobs his team has performed. Since 2018, he is co-author and lecturer at UrbanLand.PM (School of Professional Development for Project managers). Since 2021, Sergii has been as Supervisory Board Member of big Ukrainian developer, SAGA Development. When the Russian invasion began, Sergii joined the Ukrainian Armed Forces and now is serving as first lieutenant.