Reit was born in New York City on 11 November 1918 (Armistice Day; this was the source of his middle name "Victory"). He showed an early talent for art, winning a drawing contest at the age of 12. He attended DeWitt Clinton High School and New York University, where he drew cartoons for humorous college magazines. He graduated at the age of 19 and soon landed a job for $25 a week at Fleischer Studios in Miami. He worked as an in-betweener and inker on the 1939 animated film Gulliver's Travels, and later became a gag writer for the Popeye and Betty Boop cartoon series, among others. He also anonymously produced comic strips for Jerry Iger under the Fiction House label. Reit attended New York University with future Captain Marvel writer William Woolfolk; Reit helped launch Woolfolk's career as a writer of comics by introducing him to Jerry Iger and Will Eisner.

Reit served in World War II in a U.S. Army Air Force camouflage unit tasked with defending the West Coast from a Japanese invasion, and later served in Europe after D-Day. He later wrote a book, The Amazing Camouflage Deceptions of World War II, drawing on his wartime experience. It contains a version of the urban legend which claims that British aviators taunted the German Army by dropping a wooden bomb on a decoy airfield the Germans had built.

After the war, Reit did cartoon work for Archie and Little Lulu, and wrote gags for some of the new Casper animated shorts that were being produced. He also wrote for the TV series Captain Kangaroo. In 1950 he started working for the publications department of the Bank Street College of Education in New York, and also scripted industrial films and radio shows. In the late 1950s, he began submitting work to Mad Magazine, ultimately contributing over 60 pieces.

Casper first appeared in an unpublished story The Friendly Ghost written by Reit in 1940; cartoonist Joe Oriolo provided the illustrations, and the two sold all rights to the story and character for $200 to Paramount Pictures's Famous Studios division (a unit formed from the remains of Fleischer Studios). Paramount's animated short "The Friendly Ghost" based on Reit's story was released in 1945 as part of their Noveltoons series; it was well received and Casper eventually developed into an extensive franchise. In all, Casper has appeared in 55 animated theatrical shorts, hundreds of comic books, multiple television series, and several film adaptions, including a 1995 movie produced by Steven Spielberg.

Although Reit did not earn any royalties from the Casper franchise, he was content with his character's success: "All I have are some nice memories and a little nostalgic sadness that I am not part of the movie. I'm not mourning or grieving over what I might have lost with Casper. It was fun. I did the story. It has a lot of cachet."

Reit wrote over 80 books, primarily for children, on a variety of historical, technical, natural, and other subjects. One of his titles for adults, The Day They Stole the Mona Lisa, written in 1981, is about the theft of the Mona Lisa from the Louvre in 1911. In the book, Reit asserted that there were two genuine Mona Lisas in the world: the one in the Louvre, and an earlier version of the work painted by Leonardo Da Vinci which was being held in a bank vault in New Jersey (the so-called "Vernon Mona Lisa"). A long-planned movie adaptation of the book has never materialized, although the Internet Movie Database lists a movie by the same title tentatively planned for 2009.

Selected bibliography

In addition to those listed here, Reit wrote several books for Golden Press, publishers of the Little Golden Books series, and dozens of other children's books for assorted publishers.