Nao Midorikawa is one of the main heroine in Smile Pretty Cure!. She is a plucky girl with a strong sense of justice, and has no tolerance for wrongdoers. An older sister-type, she is popular even with the girls. While tough, she also has a feminine side, as she loves cute things. Excellent at sports, she is part of the girls' soccer team. Her alter ego is Cure March.
Out of the 5 girls, Nao is the tallest in terms of height. She has dark green hair worn in a ponytail at the top of her head with a yellow bow and bangs parted down the middle. Her eyes are a dark shade of green. Her casual outfit consists of a 3/4 long-sleeved yellow-green button-down shirt with multiple decorative badges, olive khaki shorts, orange socks and black boots with red laces. Her summer outfit consists of a short-sleeved light green blouse, a blue short denim skirt, khaki socks and light brown shoes. She wears her school uniform with a green tie and a pale green sleeveless pullover.
As Cure March, Nao's hair becomes bright green and much longer. The side of her bangs curl in towards her face, and her back hair is worn in a very long ponytail held with a gold barrette with an angel wing attached. Part of her hair is also worn in high twintails held up with smaller yellow barrettes. She wears her tiara on her forehead, and her earrings on the helix of her ears. Her outfit is mainly light green, with dark green lining and white highlights. Her sleeves are single-layered, and the bow at her chest is small with a large frilly piece behind it. The back of her top extends out in a single pastel green frilly piece. Her arm protectors are elbow length with light green folds on top and dark green ribbons at both the wrists and elbows. Her boots are short, with light green legwawrmers, tipped with green as well as her heels, and small dark green bows.
In Tiara mode, her white tiara is replaced by a golden crown worn in the center of her head. The centerpiece of her tiara is a green jewel, and the angel wing on her barrette turns golden as well. Her white angel wing earrings are replaced by gold ribbon-shaped earrings with green hearts in the center, and she now wears them on her earlobes.
Nao is said to have a strong sense of justice and does not easily forgive one's wrong actions. She is also known for her exceptional courage. Despite her bravery, she is a scaredy cat and have a few phobias of Bugs and heights that was revealed when the cures were shrunk by Majorina's Turn me small. She get scared easily sometimes like when she saw Miyuki and Akane headless (they were wearing Clothes, but got their helmets down) she freaked out and held on to Reika.
- March Shoot - Cure March first charges up her Smile Pact with fighting spirit, making it glow and granting her power. When enough fighting spirit has been collected, the Smile Pact explodes with wind energy that lifts Cure March off the ground and into the air. March then compresses the wind into a ball and kicks it at the enemy soccer-style.
- March Shoot Impact - An upgraded version of March Shoot, first it makes a tornado and than kicks like in soccer.
- Fire Shoot - Her combination attack with Cure Sunny used to fight together.
- In her introductory speech, Cure March says "rinrin", which has multiple meanings. Rinrin can mean "severe" or "intense", which corresponds with Nao's personality. It can also mean "piercing and cold", which may be a reference to March's power over wind.
- March is the second genuine green Cure (third if the Dark Pretty Cure 5 are counted as actual Cures).
- March is the first Pretty Cure to sport a ponytail and twin tails simultaneously.
- March is the second Pretty Cure to have her earrings on the helix instead of the earlobe, the first being Cure Sunny.
- March is the only Pretty Cure from her team to have a tiara over her forehead instead of on her head.
- March is the second Pretty Cure to control wind after Windy from Splash Star.
- Nao is the third Pretty Cure to play soccer.
- Nao is the Cure with the most number of siblings in the entire franchise.
- Nao is the only Smile! Cure to have received her powers while in casual clothes. The others all received their powers while in school clothes (Miyuki, Yayoi and Reika in their school uniforms and Akane in her sports attire).
- Nao and Rin are afraid of ghosts, but Nao are afraid insects and heights as well.
- Nao's attack "March Shoot" is nearly the same as Rin Natsuki's upgraded attack from Yes! Pretty Cure 5 GoGo! and they both involve shooting a ball of energy just like if it was a soccer ball.
- March is the only Pretty Cure in Smile Pretty Cure who, in her child form, makes the same movements as her normal aged form during her intro speech.
- Nao is the oldest Pretty Cure in Smile Pretty Cure!.
- Nao, compared to her teammates, has the least similarities with her color counterpart, Komachi Akimoto/Cure Mint.
- Interestingly, Nao shares more similarities with Rin Natsuki.
- Nao shares several similarities with Makoto Kino/Sailor Jupiter, one of the main characters from the magical girl anime Sailor Moon.
- Both of their theme colors are green.
- Both of them have their hair tied in a ponytail.
- Both of them are the fourth girls to join the group.
- Both of them are 14 years old at their first appearance.
- Both of them are athletic, despite of different reasons.
- While Nao plays soccer, Makoto practices karate.
- Both of them can cook.
- Both of them wear short boots in their respective forms.
- Nao shares some similarities with Ryuuji Midorikawa from Inazuma Eleven.
- Both have Midorikawa for their surnames.
- Both have green and similar hair-styles.
- Both can play soccer well.
- Both are often drawn to cosplay each other.
- Both are at the age of 14.
- Nao will appear as Cure March to give the 10th anniversary congratulatory message at the beginning of episode 11 of Happiness Charge Pretty Cure!