Minerva McGonagall was born to wizarding parents on October 4, 1925. She worked as the Professor of Transfiguration at Hogwart's School of Witchcraft and Wizardry from 1956 until 1998. She also served as the head of Gryffindor House during this time. After the death of Albus Dumbledore, Professor McGonagall became headmistress of Hogwart's and continued serving in that capacity for many years.
Professor McGonagall is consistently portrayed as a stern but loving figure throughout the series. She is clearly deeply attached to several of the key figures in the "Harry Potter" universe, including Harry and Hermione. She is the one who first encourages Harry to join the Quidditch team for Gryffindor and offers him help becoming an auror.
Minerva McGonagall is a skilled witch, with particular strengths in transfiguration. She is a registered Animagus. Her other form is a silvery-gray tabby cat, as seen in the "Harry Potter" films. Her Patronus also appears in the same form. She is also a talented duelist, holding her own in the final duel for Hogwart's Academy with the Deatheaters.
Professor McGonagall stands as a symbol for Gryffindor House and Hogwart's as a whole. She is unyielding character, set in her own ways. This is her strength in the series. She stands up for Harry and for the school as a whole against Dolores Umbridge and again fights for Hogwart's against the Deatheaters.
During the final battle for Hogwart's, Minerva McGonagall plays a key role. She gets young students out safely, organizes the remaining students and prepares for battle. She is a key component in Harry's journey from a child to an adult wizard, and it is alongside her that he finally comes into his own. She helps to provide him with the tools he requires to execute Dumbledore's plan and is a critical figure in the victory over the Deatheaters.