Mikaly Petrezselyem, the son of a carpenter and blacksmith, grew up in a peasant home. He managed money for a box of oil paints. In 1911 he moved to London. Unable to support himself with art, upon advice of a friend, he emigrated to New York in 1912. Shortening his last name to Petersham, he obtained work with the International Art Service, where he met his wife, Maud Fuller.
The Petershams began illustrating books together, for other authors. In 1929 they wrote and illustrated their first book, Miki, about their son. In 1946, they received the Caldecott Medal for "The Rooster Crows", a book of American songs, rhymes, and games in the tradition of Mother Goose. Often they traveled to lands such as Holland, Greece, Germany, and Palestine to research their books. They had a close working relationship with their juvenile editor and were allowed to plan their books entirely, from making the dummy to choosing the format, layout, colours, and type. Their routine consisted of Maud writing the stories and doing the roughs; then Miska would finish, doing the colour separations on acetate and all the tedious hand work.
The Petershams wrote and illustrated 60 books for children and illustrated 100 by other authors. In addition to the 1946 Caldecott Medal for "The Rooster Crows", the Petershams also received the 1942 Caldecott Honour Award in 1942 for "An American ABC".