Michael G. Hubbard, the former speaker of the Alabama House of Representatives who was convicted in a state trial last month on 12 counts of corruption, was sentenced on Friday to four years in prison plus probation and $210,000 in fines.

State prosecutors, who had been intensely criticized by Hubbard supporters for their handling of the prosecution, hailed the verdict. Calling the sentencing “a turning point in our state,” the attorney general, Luther Strange, said in a statement, “No longer can elected officials expect to disregard our laws and not pay a penalty.”

Mr. Hubbard has maintained his innocence. His lawyers, one of whom on Friday called the case “a witch hunt,” have announced an intention to appeal. They also filed a motion on Friday asking for an investigation into possible juror misconduct, attaching an affidavit from a juror who said that other jurors were making comments about Mr. Hubbard’s guilt before the trial even started.

As the architect of the 2010 Republican takeover of the State Legislature, Mr. Hubbard, 54, was often described as the most powerful politician in Alabama. His departure has added to a growing power vacuum in a state capital where the governor is facing calls for impeachment.