- Main article: Sofia Monari
Sofia Monari was the daughter of Roberto and Angelina Monari. She immigrated to the United States in 1903 from Genoa, Italy. When she arrived at Ellis Island, she was put into quarantine because she was thought to have the eye disease trachoma. This was just the first of many struggles that Sofia suffered in the new country, but nonetheless, she remained brave for her family and friends.
Gabriella Monari was the oldest daughter of Roberto and Angelina Monari and the 13-year-old sister of Sofia Monari. She immigrated to the United States in 1903 from Genoa, Italy. When she first arrived in the United States, she was upset because she wasn't able to learn English as fast as her younger siblings.
Luca Monari was the oldest son of Robert and Angelina Monari, and the 7-year-old brother of Sofia. He immigrated to the United States in 1903 from Genoa, Italy. In America, he became quite the young businessman, because he did many little jobs around Boston, earning money.
Marco Monari was the youngest son of Robert and Angelina Monari, and the baby brother of Sofia Monari. He immigrated to the United States in 1903 from Genoa, Italy. Marco often ate things he shouldn't have, and it got him into trouble one too many times.
Roberto Monari was the husband of Angelina Monari, and he immigrated with her and his 4 children in 1903 from Genoa, Italy to the United States. In the United States, he became a grocer at the Genovese Grocery Store, to provide for his family.
Angelina Monari was the wife of Roberto Monari, and she immigrated with him and her 4 children in 1903 from Genoa, Italy to the United States. In the United States, she opened a pasta shop, to provide for her family. She often tried to keep her large family in line, even though many times it was hard.
Maureen O'Malley was a 9-year-old Irish girl, who came to the United States from Killcarrick, Ireland in 1903. She got separated from her family at Ellis Island because she got stuck in quarantine because she was thought to have trachoma. Maureen became very good friends with Sofia Monari while she was in quarantine. Maureen in the book is known for standing up for what's right, in other words, she tends to get into fights with people a lot. Sofia describes her in her diary as "very brave."
- Antonia was a good friend of Gabriella Monari.
- Bridgid O'Malley was a sister of Maureen O'Malley, she came from Killcarrick, Ireland with her family in 1903.
- Caesar was a pigeon who delivered messages from Sofia to Maureen, and Maureen to Sofia.
- Captain Grandby owned a ship in Boston and was associates with Luca Monari.
- Chiarina was a good friend of Sofia Monari. Chiarina is Italian like Sofia and speaks very good English, and she is part of the Lilies of the Arno club at Paul Revere School.
- Cookie was the kind cook on Captain Grandby's ship in Boston.
- Corrado Genovese was the husband of Thomasina Genovese and the father of Mirella Genovese. He owns Genovese Grocery Store, and unlike his wife and daughter, he acts very kindly to the Thomasina Genovese.
- Declan O'Malley was a brother of Maureen O'Malley, he came from Killcarrick, Ireland with his family in 1903.
- Doctor Gerardo Balboni was a very kind doctor who lived in Boston. He became very good friends with the Monari family.
- Doctor Burnet was the father of Ms. Burnet who lived in Cambridge, Massachusetts. He became good friends with Sofia.
- Doctor Cochrane was a mental doctor who worked in quarantine on Ellis Island in 1903.
- Doctor Gilbert was a mental doctor who worked in quarantine on Ellis Island in 1903.
- Father Finnegan was a pastor who worked on Ellis Island in 1903. He helped free Maureen O'Malley and Sofia Monari from quarantine, so they could return to their families.
- Franco was a sailor on the steamship the Florida in 1903. He was associated with Roberto Monari.
- Fredo was Luca Monari's Italian friend who lived across the hall.
- Gennaro Romagnoli was a man who sent messages to others by pigeon. Sofia Monari pays Gennaro to send a pigeon with a message to her best friend Maureen who lives in Brooklyn, New York.
- Giuliana Forte was a very smart girl who went to Paul Revere School.
- Giusepe was 14 when he immigrated from Italy to the United States, in 1903 aboard the steamship the Florida. He was the nephew of "Signora Salami" and he had a crush on Gabriella Monari.
- Great Auntie Mirella was the great aunt of the four Monari children. She was a nun at the convent of Santa Giustina dei Monti. She wanted her great-niece Gabriella, to become a nun like her.
- Isabella Stewart Gardner was a very famous and rich lady in Boston. Gabriella was one of her seamstresses'.
- Joe was a man who was stuck in quarantine on Ellis Island. He was friends with Sofia and Maureen. He was described by Sofia as having "a simple mind."
- John Singer Sargent was a man who worked for Isabella Gardner, and his job was to go and buy paintings for her,
- Lillian Barron, referred to as Mean Nurse, was a nurse who worked in quarantine on Ellis Island in 1903. She was rude to Mr. Joe, Maureen, and Sofia Monari. She also tried to poison their milk once.
- Lillian Dobie is the fiance of Doctor Balboni, and she worked as a nurse at Massachusetts General Hospital.
- Mademoiselle Coco was a seamstress in Paris. She sewed costumes for a dancing show called the Folies Bergère. She came to the United States after her heart was broken. She wore a wig because she burned her scalp with dye and because of this the doctors on Ellis Island that she was sick.
- Malachy O'Malley was a brother of Maureen O'Malley, he came from Killcarrick, Ireland with his family in 1903.
- Mirella Genovese was the daughter of Corrado Genovese and Thomasina Genovese. Her father owned Genovese Grocery Store. Mirella was very stuck-up and always acted very rudely to Sofia. Sofia's younger brother Marco also swallowed the glass eye of one of Mirella's precious dolls, which makes Mirella despise Sofia even more.
- Mirka Cohen is a friend of Sofia Monari. Her family owned Cohen Dry Goods on Salem Street. Mirka was Jewish and was part of the Wiltsie Club at Paul Revere School.
- Miss Bradshaw was Angelina Monari's teacher at the North Bennet Street School. She loved Angelina's tortellini.
- Miss Burnet was Sofia's 3rd and 5th-grade teacher at Paul Revere School. Ms. Burnet was very kind to Sofia and became Sofia's favorite teacher.
- Miss Coggins was Sofia's 4th grade teacher at Paul Revere School. Sofia didn't really like Miss. Coggins, though.
- Miss Gillespie was the secretary at the North Bennet Street School. She loved Angelina Monari's tortellini.
- Miss Walker was a kind teacher, who taught Gabriella at a sewing school in Boston.
- Molly was an Irish friend of Gabriella Monari. She took sewing lessons to become a maid like her older sister.
- Mrs. Del Orio was the leads the projects of the Lilies of the Arno Club at Paul Revere School.
- Mrs. Wedge was a kind seamstress with bad arthritis. Gabriella helped her with her sewing.
- Nancy, referred to as Nice Nurse, was a nurse who worked in quarantine on Ellis Island in 1903. She was kind to Maureen and Sofia.
- Nellie Melba was a famous Boston singer and sang at Isabella Gardner's New Year Party.
- Nina was a good friend of Gabriella. She helped play a trick on Sofia on Halloween 1903.
- Pauli was the older brother of Sofia's friend Chiarina. He got to play Christopher Columbus in the Columbus Day Assembly at Paul Revere School.
- Pietro was Luca Monari's friend, from back in Genoa, Italy.
- Rafi "The Shadow" was a gypsy boy who lived by Ellis Island. He became friends with Mademoiselle Coco, Maureen, and Sofia Monari.
- Rose Fitzgerald was the daughter of the retired congressman, John Fitzgerald. Sofia's sister Gabriella described Rose as "one of the most beautiful girls she had ever seen."
- Signora Salami was a woman who was aboard the steamship the Florida in 1903, with her nephew Giuseppe. "Signora Salami" was a nickname given to her by the Monari kids, because of how she smelled like soppressata (the smelliest of all salamis.) In the book, we don't know her real name.
- Sister Lucia was a kind nun who helped with the Lilies of the Arno's meetings. She stood up to Mrs. Genovese whenever she was rude.
- Thomasina "Tomi" Genovese was the wife of Corrado Genovese, and the mother of Mirella Genovese. Her husband owned Genovese Grocery Store. She acted very rudely to the Monari family, especially Angelina and Marco Monari. Sofia nicknamed her Tomi.
- Uncle Gian Carlo was Sofia Monari's uncle, who worked at a pasta factory near Bologna, Italy.