He started working as an arranger for several United States Navy big bands in the mid-1940s during his service in World War II, including Jimmie Lunceford's black orchestra.
[2] He appeared prominently in the 1956 Alan Freed film, Don't Knock the Rock, and worked for a while as the studio band and music director on the Ernie Kovacs TV and radio shows in Philadelphia.
Next Appell and the Applejacks were playing in Las Vegas, but they soon began to pine for their hometown and returned to Philadelphia, where they started working for Cameo Records, a label founded by Kal Mann and Bernie Lowe.
In the cases of the aforementioned act's records Appell also arranged and, in many instances, produced, and even co-wrote with Kal Mann, songs such as "Let's Twist Again", "Bristol Stomp", "Mashed Potato Time", and "South Street".
In the 1970s he had success with his productions for Tony Orlando and Dawn, including the # 1 hits "Knock Three Times" (1970) and "Tie a Yellow Ribbon Round the Ole Oak Tree" (1973), on Bell Records in New York City.