Millar worked on CARtoons until 1963, when he was replaced by Hot Rod editor and "Stroker McGurk" creator Tom Medley.

[3] Drag Cartoons featured early adventures of Gilbert Shelton's iconic underground comix character Wonder Wart-Hog, who appeared in many issues.

In 1968, Millar and his wife and three daughters left the U.S. and traveled through Europe, living in Sweden and Spain, and touring Finland, the Soviet Union, and other Eastern Bloc and Mediterranean countries.

Millar financed much of their trip through illustration work for American magazines; he also began making fine art paintings.

[2] Millar was also a bronze sculptor with his main emphasis focus being Western art depicting dramatic scenes of horseback riding, cowboys, bronco riders, mountain men, Native Americans, and more.