JERUSALEM—Former Israeli Prime Minister Ehud Olmert was sentenced to eight months in prison for unlawfully accepting money from a U.S. supporter.

Monday's verdict in Jerusalem District Court caps a dramatic downfall of a man who only years earlier led the country and hoped to bring about a historic peace agreement with the Palestinians.

Mr. Olmert was convicted in March in a retrial. The sentencing comes in addition to a six-year prison sentence he received last year in a separate bribery conviction, ensuring the end of the former premier's political career.

Mr. Olmert's lawyers said they would appeal the ruling.

Mr. Olmert was forced to resign in early 2009 amid the corruption allegations. His departure cleared the way for hard-liner Benjamin Netanyahu's election. Subsequent peace efforts haven't succeeded.