The story features a well-to-do British family in the early 1900s. Mother is busy fighting for women's right to vote, no-nonsense Father makes his living at the bank, and the two young children need a Nanny. To the rescue comes Mary Poppins (Julie Andrews). She is "practically perfect in every way", and is magic as well. Dick Van Dyke, a street merchant and chimney sweep, shows up now and then to help entertain the kids.
Mary Poppins has a nifty sequence that combines animation and live action. This fantasy may be the best part of the movie. There is similarity between this film and Peter Pan, another Disney animated film where British children are entertained by a magic figure who is only temporarily in their lives.
If Mary Poppins is lacking anything, it is dramatic tension. The only resistance to Mary comes from Father, who wants to prepare the children for the "real" world of work and drudgery. With Father being so tiresome, Van Dyke serves as a surrogate, more friendly and free-spirited. Father does have a character transformation by the end of the film, which could alternately be considered a nervous breakdown.
The musical numbers have contagious melodies and clever lyrics. They work well until a chimney sweep sequence that goes on for too long and features synchronized dancing and singing by every chimney sweep in London.
Mary Poppins does have excellent casting. It is difficult to think of any role that could have been filled by someone more suitable.
Mary Poppins was the final film in the career of veteran character actress Jane Darwell (The Grapes of Wrath, The Ox-Bow Incident), who plays the bird woman.