Seyoum made aliyah to Israel from Ethiopia in 1984 at the age of 13.^[1] His family initially lived in a Jewish Agency absorption centre in Netanya, and Seyoum went on to attend a boarding school.^[1] During his national service, he was a physical education instructor.^[1] After leaving the army, he worked in Kfar Haroeh at Ben Yakir for eight years.^[1] He later worked at the Wingate Institute, before becoming director of country's largest immigrant absorption centre in Safed.^[1]

After joining the new Kulanu party prior to the 2015 elections, Seyoum was placed fourteenth on the party list.^[2] Although the party won only ten seats in the elections, Seyoum entered the Knesset on 2 January 2019 as a replacement for Yoav Gallant.^[3] Despite being moved up to eighth place for the April 2019 elections, he lost his seat as Kulanu were reduced to four seats.

• Fentahun Seyoum on the Knesset website