He was elected by his colleagues Wednesday on a 107-2 vote.
Such votes typically are unanimous, but two Democrats voted against Bolger leading the chamber for two more years.
An Ingham County judge acting as a one-person grand jury is collecting evidence to decide whether to charge Bolger or anyone else with crimes in a Democratic lawmaker's switch to the Republican caucus in May. The Kent County prosecutor said Bolger and then-Rep. Roy Schmidt broke no laws, but that their actions represented a fraud on the public.
Bolger has apologized, but insists he broke no laws.