The Great Minnelli Family
If you're not a film buff, you may not know who Vincente Minnelli is, but you've heard of his daughter Liza Minnelli, lately known for her role as Lucille 2 on everyone's fave aughts comedy, Arrested Development. Her mom was none other than MGM superstar Judy Garland, and there's no doubt that entertainment genius was in the family DNA. In fact, Vincente Minnelli's parents were touring theatrical types as well, and he began his time in the theatre as a costume and set designer.
Style as Substance
By the time he directed his first film in 1943, Minnelli was starting to develop his colorful directorial eye. Throughout his thirty-plus year career, he created such classics as Meet Me in St. Louis, An American in Paris, Father of the Bride, and of course, Gigi. He was known for using saturated color (which, in the '40s, was still a relatively new option), and melding drama and comedy into movie perfection.
In his films, everything is a bit bigger and brighter than life. Transformations—less ugly duckling to beautiful swan than beautiful swan to even more beautiful swan—crop up often, as do narrators (Honoré, or the dad in Father of the Bride). Minnelli was known as a stand-up studio guy who could make a good (or at least serviceable) product from any script (source).
Everyone's A Critic
Legendary director Peter Bogdanovich called Gigi one of "Minnelli's least effective works—a not very interesting project done without his usual sparkle or flair; on the contrary, an almost graceless, strangely wooden work, overwhelmed with mediocre Beaton sets and costumes, and uncomfortable actors" (source). So keep that in mind if Gigi is the first Vincent Minnelli movie you've seen, even if Bogdanovich's opinion isn't the majority view.