He served in the Legislative Assembly of Alberta from 1935 to 1948 as a member of the Social Credit caucus in government.

Popil first ran for public office as a Social Credit candidate in the 1935 Alberta general election.

He defeated incumbent cabinet minister John Love and four other candidates on ballot transfers in the electoral district of Sturgeon.

[2] After Sturgeon was abolished in the 1940 boundary redistribution, Popil ran for a second term in office in the new Redwater electoral district in the election held that year.

He marginally increased his popular vote and won a big majority to hold his seat.