He is the Chairman of the Liepaja Special Economic Zone Authority, the Liepāja Party, the Liepaja Development Fund and a member of the Rotary Club. He studied at Liepaja school № 6. Sesks graduated from the Latvian Academy of Agriculture in Jelgava with a degree in mechanical engineering. From 1986-1987, he was chief of the transport department of kolhoz Zelta zvaigzne. From 1987-1992, he was the vice-president of the board of kolhoz Zieds in Vecpils. He improved his knowledge of entrepreneurship in Germany within a cooperation project with the North Rhine-Westphalia Chamber of Commerce.
In the 1980s, he was active in Auto racing. At the beginning of the 1990s he established a private company "Autocentrs", which was later reorganized into "SD Autocentrs" and became the dealer of Volkswagen in Liepāja. He sold his share of the company in 2004.
In 1997, Sesks was elected the Chairman of the Liepaja City Council (Mayor) and re-elected to this position in 2001 and 2005. At the end of 2004 he established the Liepāja Party which has a cooperation agreement with the Union of Greens and Farmers.
He is married with two daughters Baiba and Anete and one son Mārtiņš Nikijs.