Together, Millikin and Casey Sorrow created and popularized the international animal rights holiday World Monkey Day.

[6] He began drawing horror art by age one-and-a-half, and by second grade, he was making teachers profane birthday cards showing his school burning down.

He has championed Barack Obama's Patient Protection and Affordable Care Act, commonly referred to as "Obamacare".

"[95] Millikin has also used his artwork to raise money for causes like helping Hurricane Katrina victims,[96] fighting diseases like muscular dystrophy,[97] and granting wishes to terminally ill children through the Make-A-Wish Foundation.

[98] He has also created posters campaigning to raise money for programs to improve adult literacy,[99] auctioned artwork to support soup kitchen efforts to feed the hungry,[87] and created artwork to help people in the city of Flint who had lead-contaminated water during the Flint water crisis.

[107] His artwork critical of alleged lies by Detroit Mayor Kwame Kilpatrick was part of the portfolio that won the 2009 Pulitzer Prize in local reporting.

"[116] Millikin's work has also been nominated for multiple Web Cartoonists' Choice Awards, including their top honor of "Outstanding Comic".

[128] Congressman John D. Dingell displayed it on the House floor urging passage of government loans to automakers and reiterated the central theme of the piece, saying "now is the time for us to 'Invest in America'.

"[129] Millikin's work has also been praised by ESPN's Mike Tirico during a 2011 Monday Night Football half time show.