Frank Engli was born in 1906 in Chicago as the son of Hungarian immigrants. In the same city he studied at the Academy of Fine Arts and the Art Institute. After graduation, he hitch-hiked through the country, taking on several odd jobs, including a stint as art director for Western Electric in Kearny, New Jersey. His graphic career took off when he created one-panel gag cartoons for a while. Between 1928 and 1929 he assisted Milton Caniff on several of his early comics which appeared in the Columbus Dispatch in Ohio. By 1930 he worked as a commercial artist at an electric company in Manhattan, New York City. From 1932 on Engli was a letterer for Bill Dwyer's newspaper comic 'Dumb Dora'.
In 1933 Engli became an animator at the Fleischer Studios in Manhattan. There he worked on many cartoons starring 'Popeye' and 'Betty Boop' until about 1936. From 1934 he worked as a letterer and colorist on comics by Milton Caniff and Noel Sickles, including 'Terry and the Pirates', 'Male Call', 'Steve Canyon' and 'Scorchy Smith'. He stayed with Caniff until his retirement in 1977. Engli also did occasional work for Harvey Comics.
Apart from helping other cartoonists Engli had his own comic series as well. On 1 October 1933 he created the aviation comic 'On the Wing' starring the pilot Mack Martin, his sidekick Bumpy and Mack's girlfriend Mary Miller. Engli was also well known for his humorous comics set in the Stone Age, such as 'Rocky the Stone Age Kid', which ran from 25 August 1940 to 31 October 1943 in the Chicago Tribune Comic Book, and 'Looking Back', which appeared between 30 December 1945 and 25 May 1947, distributed by Field Enterprises.
Engli passed away in 1977 in L.A.