CAIRO—Hosni Mubarak was released from prison to house arrest on Thursday, Egyptian media showing images of the 85-year-old former autocrat smiling as he was wheeled on a gurney from a helicopter after his airlift from the penitentiary.

News of his release caused barely a ripple of reaction from a country still reeling in the violent struggle for power in the wake of his nearly 30-year rule.

Mr. Mubarak was transferred to a military hospital in the Cairo suburb of Maadi, where former leader is expected to continue his convalescence. He is scheduled to appear in court again on Sunday to address murder charges for failing to prevent the deaths of protesters during the revolution that ousted him.

Mr. Mubarak's release follows a tumultuous 2½ years after mass protests pushed him from office in February 2011. Last month, Egypt's military was backed by legions of protesters in pushing aside Mr. Mubarak's successor, President Mohammed Morsi, the country's first freely elected president. Since then, fighting between Mr. Morsi's mostly Islamist supporters and security forces has claimed more than 1,000 lives.

On Thursday, outside the notorious Tora prison south of Cairo, about a dozen supporters carrying portraits of Mr. Mubarak gathered to celebrate his release.