John Coger "Jackie" Martling Jr. (born February 14, 1948) is an American stand-up comedian, writer, radio personality, author, actor, and musician also known as Jackie the Joke Man. He is best known as a former writer and in-studio comedian for The Howard Stern Show from 1983 to 2001.

Born and raised on Long Island, New York, Martling began a career in stand-up comedy in 1979, developing a blue comedy act in local venues. He self-produced his first of three comedy albums, What Did You Expect? (1979), during this time. After becoming involved with Rick Dees's radio show as a regular joke feature, Martling sent his albums to New York City radio personality Howard Stern, who invited him as a weekly guest and writer in 1983. This led to his hiring as head writer from 1986 to 2001. He released further albums during his tenure, including Sgt. Pecker (1996), Joke Man (1996), Hot Dogs + Donuts (1998).

Since his departure from The Howard Stern Show, Martling has undertaken various projects, including acting roles in television and film, and continues to perform stand-up. From 2006 to 2014, he was the host of Jackie's Joke Hunt on Sirius XM Satellite Radio, on Howard Stern's channel. He released his first music album, Happy Endings (2008). Martling has written two books, Disgustingly Dirty Joke Book (1998) and The Joke Man: Bow to Stern (2017).

Martling was born on February 14, 1948, in Mineola, New York, a village on Long Island. The eldest of four children, he is of English, French, and Dutch ancestry. Martling took up music at seventh grade and spent time as a gymnast in his youth. He attended James H. Vernon School in East Norwich, New York, followed by Oyster Bay High School and, in 1971, earned a mechanical engineering degree from Michigan State University. After graduating, he stayed in East Lansing, Michigan, for a further two years. During his time in college, Martling was the singer and guitarist in a band. He quit the group and spent six months in Denver, Colorado, working in construction.

After returning to New York, Martling became the singer and guitarist in The Off-Hour Rockers alongside guitarist Chris Bates and keyboardist Herbie Werner, whom he incorporated jokes, banjos, and the kazoo with in the band's sets. He also performed solo shows and told jokes during his act. In order to accommodate the band's gear, Martling drove a used hearse. Martling began taking stand-up comedy more seriously in 1976, after he attended an open-mic night at Catch a Rising Star comedy club in New York City. "The auditioner bailed out early and the MC wasn't in the room, so I jumped on stage and told a joke, one that I was sure the entire world knew. The MC, David Sayh, came back in the room and saw me up there but let me finish". Sayh encouraged Martling to continue performing as a joke teller, and soon found out that "few people knew any of the zillions of jokes I knew".

By 1979, Bates and Werner disbanded the Off Hour Rockers to start a new group. At that point, Martling started to pursue stand-up comedy full-time, developing his stage act of songs and dirty jokes. During a gig at My Father's Place in Roslyn, New York, Martling met the likes of comedians Eddie Murphy, Rob Bartlett, and Bob Nelson who would perform for several minutes at Martling's gigs. In 1979, he set up a "dial-a-joke" telephone line from his parents' attic, Jackie's "Use Your Finger! (516) 922-WINE", which remains in operation to this day. Also in 1979, Martling released his first comedy album, What Did You Expect?! (1979), which he recorded himself using his own recording equipment. This was followed by Goin' Ape! (1980). Martling made a breakthrough in 1981 when Dave Lipson, writer and producer of Rick Dees's morning radio show on KIIS in Los Angeles, discovered his joke line and played his daily joke updates on Dees's program. The exposure led Martling to star in a designated joke segment for Dees, who went on to give Martling his nickname, "The Joke Man". Also in 1981, Martling released his third album, Normal People Are People You Don't Know That Well (1981).

Martling first heard of radio personality Howard Stern in August 1982 when the owner of Washington, D.C.'s Garvin's comedy club, where Stern had occasionally broadcast from during his time at WWDC (DC-101), suggested to Martling that he send his comedy albums to the recently fired radio DJ who had since landed at WNBC in New York City. By early 1983, Martling had mailed his three comedy albums to Howard Stern, then less than a year into his stint in afternoons at WNBC. Stern took a liking to Martling's material and invited him on as a guest in February 1983, which soon turned into a weekly guest spot without pay. Stern then began a regular segment titled "Stump The Comedian", a contest where callers were challenged to start a joke that Martling had to provide the punchline to, otherwise they win prizes.

In 1985, following the show's cancellation from WNBC, Stern stayed in New York City and relocated to afternoons on WXRK. Martling was subsequently hired as a writer on The Howard Stern Show when it moved to the mornings slot in February 1986, initially for two days a week. After around two months, Martling was hired full-time and became known as the head writer who would take lines written by himself and sound effects and producer Fred Norris and "determine what goes in front of Howard". Along with Norris, Martling contributed material to radio bits and song parodies and is featured and credited on Stern's television shows, home videos, and albums. In 1994, a puppet that resembled Martling, known on the show as the "Jackie puppet" and voiced by show impressionist Billy West, began to feature on the newly-launched Howard Stern television program on the E! channel.