This story is centered on a first grader named Mido McAndrew, and he wins a song contest. Consequently, he becomes a famous pop singer--but underneath, he is a kind, independent kid with dreams.
- Mido McAndrew - The focal character of the series. His birthday is November 7, and he is of Irish and Ukrainian descent on his dad's side and of Italian and Welsh descent on his mom's side. He can play vocals, keyboard, and piano, and he was the younger one born out of the McAndrews. Mido is in first grade.
- Ashling McAndrew - Ashling is the older one of the McAndrew kids, and her birthday is October 12. She is concerned about the things that most normal seventh-grade girls are concerned about, such as makeup and fashion. She knows how to play electric guitar and violin.
- Joanne "Mom" McAndrew - Joanne is Mido and Ashling's mom, but she is referred to as "Mom" throughout the story. Her birthday is June 26.
- Miss Jasinski - Miss Jasinski is the Polish-American manager of Mido McAndrew. She was once a professional singer too, and her birthday is February 26.
- Daniil McAndrew - Daniil is the older sibling of Yulia, Mido, and Ashling. He is in college, and his birthday is May 18.
- Yulia McAndrew - Yulia is the younger sibling of Mido, and she is in kindergarten. She can't play any instruments (she tried piano lessons, but she quit). She is a backing vocalist for Mido. Her birthday is September 22.
- Hana Hashimoto - Hana is the Japanese-American host of the Hanavision, a song contest for aspiring singer-songwriters in the age range of five to sixteen. Her birthday is January 3.
- Ben - Ben is the French-Irish-American classmate of Mido. Ben is a goofball, and is known for acting nuts and taping hamburgers to his shirts. His birthday is August 6.
- Rebecca Grimes-Little - Rebecca is the Senegalese-American classmate of Mido. Her birthday is March 18, and she plays the violin.
- An Teng - An is the Taiwanese-American classmate of Mido. An's birthday is July 29, and he is always knocking down the other kids' blocks.