The 30-year-old suffered a head injury in the collision, which happened in the early hours of Saturday.
The man was hit by a Vauxhall when he was walking along John Knox Street, near Wishart Street, at around 3.45am.
The 48-year-old car driver contacted emergency services. He was not hurt but is said to have been left very shaken by the incident.
The man who was hit was initially taken to the nearby Glasgow Royal Infirmary but was later transferred to the Southern General.