[1] Ummi was born in Tootsi, and graduated in 1988 from the University of Tartu, faculty of law.
[1] Arumäe was registered as a member of the conservative Pro Patria Union between 1998 and 2010, and the centrist Estonian Centre Party between 2009 and 2011.
[2] After being admitted to the Estonian Bar Association in 1994, he founded his own law firm, while also being active in the public sector by working in local government.
In 2010, he defended his doctoral dissertation entitled Territorial communities and the Legal Organization of their Management at the Estonian Business School and acquired a doctorate (PhD) in management science.
From 2005 to 2008, he was the mayor of the Viimsi Rural Municipality and chairman of the Harju County Local Government Association (2006–2010).