He speaks in a loud and overly-enthusiastic staccato voice (like a radio DJ or beer commercial pitchman) and does a lot of exaggerated physical movements like a male exotic dancer – like dancing in place, groin-thrusting, hip shaking, and rubbing his buttocks with a towel.

Some of the actors who play him have actually died (presumably from alcohol-related causes, analogous to the Marlboro Man); their demise was never acknowledged because the character of Duffman is unaging and immortal.

[7] In "Burns Verkaufen der Kraftwerk", Homer celebrates a recent minor stock windfall by ordering a bottle of Henry K. Duff's Private Reserve, which is implied to be more costly and of better quality, and which is an apparent spoof of Henry Weinhard's Private Reserve,[8] as well as alluding to Hendrik Doeff, the Dutch commissioner of the Dejima trading outpost, who first introduced beer to Japan.

In the season 21 episode "To Surveil With Love", Duffman makes a giveaway of Duff advertising in Moe's bar while "Get Ready For This" by 2 Unlimited plays on the background, suggesting this might be the theme song for the beer brand or for the character.

Fudd, a competitor to Duff, appears in the episodes "Colonel Homer" and "Lemon of Troy", the latter showing it being enjoyed by residents of Shelbyville, rival town to the Simpsons' home of Springfield.

Other Duff Gardens attractions include the Beeramid, the Beerquarium ("Home of the world's happiest fish"), the Beer Hall of Presidents, the Washing Machine ride, the Whiplash rollercoaster, singing group Hooray for Everything (who sing a politically correct version of Lou Reed's "Walk on the Wild Side" and are based on Up with People), and a direct parody of Disneyland's Main Street Electrical Parade.

[14] In response McKagan has stated that he thought it was common knowledge and uncontroversial that he was the origin of the name, and jokingly called assertions to the contrary "absurd.

[16] Matt Groening, the creator of The Simpsons, said he would not license the Duff trademark to brew an actual beer, over concern that it would encourage children to drink.

Bilbo's pizza and brewery in Kalamazoo, Michigan also brewed their own form of Duff beer, which had a Homer Simpson tap handle to complete the reference.

[24] Duff Beer UG applied for an EU Community Trade Mark (CTM) in 2009, which was opposed by Twentieth Century Fox.

[25] In 2011 the Office for Harmonization in the Internal Market decided in favour of Fox, and in 2012 Duff Beer UG appealed to the European Court of Justice (ECJ).

[27] Fox's CTM was cancelled by the OHIM in 2011,[27] following a 2010 ruling by the Brussels Commercial Court that a "Beer" logo applied exclusively to non-beer merchandise was misleading.

[32] While news reports of its 2011 introduction mentioned The Simpsons,[33] its own website does not, although it refers to its "iconic packaging" and states "The product has certainly fulfilled its namesake in becoming a modern day legend".

[32] In the mid 1990s, the Lion Nathan brewery in Australia produced a beer called Duff, which resulted in 20th Century Fox bringing legal action against the company.

[24] In May 2014, another incarnation of Duff was launched and sold through the Woolworths chain, but was pulled from Australian shelves on September 8 after a complaint to the Alcohol Beverages Advertising Code adjudication panel was upheld over concerns over the product's appeal to minors.

[35][36] The Investigations Police of Chile seized 60,000 bottles of Duff-brand beer in the city of Linares following an intellectual property complaint from 20th Century Fox in March 2013.

[42] Since French television has a strict prohibition on advertising and product placement of alcohol, subsequent broadcasts of The Simpsons have blurred the Duff logo on screen.