Initially working as an intern, Melendez became known for asking celebrities impertinent questions at events and press conferences with his stuttering.
Over time, Melendez became known for segments in which he asked celebrities confrontational questions at red carpet events, functions, promotional appearances, and press conferences.
The puerile questions—written by Howard Stern, Fred Norris, and Jackie Martling—centered around a given celebrity's private life and were premised on the idea that they would not want to look bad by refusing an interview from someone who stuttered.
The absurdity of the questions Melendez asked was often amplified by the fact that he himself appeared to lack common pop culture knowledge and often did not even seem to know who the subjects of his interview were or why they were famous.
[6] At Gennifer Flowers' news conference playing the 'Clinton Tapes', he asked her if she planned to sleep with any other candidates before the election, to which she reacted by laughing.
[9] Melendez started receiving U.S. national exposure in the early 1990s[9] as Stern's syndicated morning radio show acquired more markets (including Los Angeles and Cleveland) and particularly from June 1994 when its condensed version began airing nightly on E!
[6] During his 15-year run as Stern's employee, Melendez also starred in the Off-Broadway show Tony n' Tina's Wedding where he met his future wife, Suzanna.
He has also appeared on television in episodes of Wings, Baywatch Nights, and the 2003 United States version of the reality series I'm a Celebrity... Get Me Out Of Here!.
Throughout the early part of 2002, Melendez and WXRK afternoon deejay Lee Mroszak (aka "Crazy Cabbie") had numerous on-air spats, which were used by Stern as fodder for multiple segments on the show.
Their feud eventually culminated in a boxing match scheduled for Friday morning May 31, 2002, at Trump Taj Mahal in Atlantic City and was promoted on the show as "The Flunky versus the Junkie" with 2,500 tickets going on sale for $100 each.
Billed as "Win John's Job" (much like "Win Jackie's Money" after writer Jackie Martling walked out), the contest resulted in the hiring of Sal Governale (aka "Sal the Stockbroker") and Richard Christy, although for several years, L.A. radio disc-jockey "Scary Gary" (from 97.1 KSLX, which played Stern's radio show in Southern California) did Stuttering John style interviews that Stern would play on his show.
In August 2020, Melendez sued the Liberty Media-majority-owned satellite and online radio platform Sirius XM Holdings Inc. for "using his name, likeness, and voice without permission" on its two channels dedicated to The Howard Stern Show and related content.
[12] Filed in the Manhattan-based U.S. district court, the complaint sought unspecified damages for Sirius XM's airing of old recordings of Melendez from his time on The Howard Stern Show, with Melendez claiming such action violated California law and his right of publicity while further estimating that more than 13,000 hours of the then-syndicated morning radio show feature his voice, name and identity which Sirius XM benefits from by selling advertising without compensating him.
[13] The judge's written ruling further stated that Melendez did not show he was injured or that Sirius XM illegally used him to promote its services, adding that "the commercial advantage Sirius XM gains from playing The Howard Stern Show archives and running the advertisements flows from the rebroadcasting of the copyrightable sound recordings themselves, not from Melendez's identity”.
[13] Melendez's lawyer commented that the judge “adopted a unique analytic framework which we believe is inconsistent with prevailing law" while announcing the intention to appeal the ruling.
During Melendez's podcast on June 28, 2018, he prank-called the White House by pretending to be an assistant to Senator from New Jersey, Bob Menendez.
Melendez then impersonated Senator Menendez and had a four-minute conversation focusing on immigration reform and the Supreme Court vacancy.
[23] On July 2, 2018, Melendez announced that he had retained lawyer Michael Avenatti to represent him in relation to the prank call after being visited by Secret Service agents over the previous weekend.
[25] After moving to California in 2004 to work on The Tonight Show, Melendez lived in Calabasas with his wife Suzanna Keller and their three children.