Except in a city having a combined police and firefighters’ civil service commission, the commission shall consist of three members who are citizens of the state and resident of such city, and shall be appointed by the council of the city, and when first created one commissioner shall be appointed for the term of one year, who shall be president of the commission, one for the term of two years, and one for the term of three years, and all commissioners shall hold office until their successors are appointed and qualified. The council may remove any commissioner who in the judgment of the council has willfully violated any of the provisions of sections 420.01 to 420.16. No commissioner shall, at the time of appointment or while serving, hold any other office or employment under the city, the United States, the state of Minnesota, or any public corporation or political division thereof, other than the office of notary public or member of a civil service commission for police officers or other municipal personnel. Each commissioner, before entering upon duties, shall subscribe and file with the city clerk, an oath for the faithful discharge of the duties. Except in a city having a combined police and firefighters’ civil service commission, there shall be appointed each year thereafter by the council one member of the commission whose term of office shall be for three years, and each member of the commission shall be president during the last year of the term. All vacancies in the commission shall be filled by appointment by the council within 90 days after the vacancy occurs.