Piven was born in Manhattan and grew up in Evanston, Illinois, a suburb north of Chicago. He graduated from Evanston Township High School, and attended Harand Theater Camp in Elkhart Lake, Wisconsin, as a teenager. He played the part of "Bernardo" in West Side Story there. In Illinois, he trained at Piven Theatre Workshop, founded by his parents, Byrne Piven and Joyce Piven, both of whom were actors and drama teachers. He also attended Drake University in Des Moines, Iowa, and is a member of the Pi Kappa Alpha Fraternity. He spent a semester at the National Theater Institute in Waterford, Connecticut. He has appeared in a number of films with John Cusack, who is also from Evanston and is a fellow alumnus of the Piven Theatre Workshop (as are Cusack's sisters Joan and Ann). Piven and Cusack once shared an apartment and have been friends since high school.

Piven's first significant role came in 1992 when he became as a regular cast member on HBO's The Larry Sanders Show, where he played the head writer Jerry. In 1993, he portrayed George Costanza on the show-within-a-show scene in the Seinfeld episode, "The Pilot". Piven has appeared in several successful films, including Lucas, Grosse Pointe Blank, Singles, Very Bad Things, The Family Man, Black Hawk Down, Heat, PCU, Old School, Rock N Rolla, Smokin' Aces, and Runaway Jury. He has also had brief cameo appearances in Rush Hour 2 and in the US release of Cars.

Since 2004, Piven has reinvigorated his career by playing a fast-talking, acerbic Hollywood agent Ari Gold in the HBO series Entourage. He received Emmy nominations for best supporting actor four straight years from 2005 to 2008, and won the award in 2006, 2007, and 2008. 2009 was the first year in which he didn't receive an Emmy Award nomination for his work on Entourage. Piven was also the star and producer of the short-lived ABC dramedy series Cupid, and was a supporting cast member on the last three seasons of the sitcom Ellen. He played the part of Ellen's cousin, Spence. He also voiced Elongated Man in three episodes of Justice League Unlimited.

In 2007, Piven appeared in the video for "Drivin' Me Wild", the third single taken from rapper Common's seventh album Finding Forever. The two were co-stars in Smokin' Aces, and appeared together when Piven hosted SNL in January 2007.

Piven appeared in the first Broadway revival of David Mamet's Speed-the-Plow, co-starring Mad Men star Elisabeth Moss and three-time Tony nominee Raul Esparza. The production began preview performances on October 3, 2008, and opened on October 23, 2008; the play was due to run through February 22, 2009. After Piven missed several performances, on December 17, 2008, Piven's rep announced that due to an undisclosed illness, Piven would be ending his run in the play effective immediately. The illness was revealed to be hydrargaria, a disease caused by exposure to mercury or its compounds, though the source is unknown. Rumours have indicated that the high level of mercury could potentially have been caused by Piven's habit of consuming fish twice a day for the past 20 years. An alternative explanation is that the herbal remedies Piven was taking were responsible for his high levels of mercury. Mamet joked that Piven was leaving the play "to pursue a career as a thermometer". On September 1, 2009, Piven, in a guest appearance on Late Show with David Letterman, explained that he had given up red meat and poultry, and had been getting all of his protein from fish for the past twenty years. William H. Macy and Norbert Leo Butz replaced Piven in the Broadway show.

Piven considers himself a Jewish Buddhist. He starred in the Travel Channel special Jeremy Piven's Journey of a Lifetime detailing his journey across India.

Jeremy Piven opened up on Speed-the-Plow and the mercury poisoning controversy on July 2, 2010, with ABC News, setting the record straight on the severe mercury poisoning that kept him from being able to continue his performance. In the interview, he described his desire to embody the spirit of the "show must go on" mentality, however, doctors had expressed to him that he could literally "die on stage".

Albert Lodge

14. omg!.yahoo.com, Piven on "Speed-The-Plow" and Mercury Poisoning, http://omg.yahoo.com/videos/piven-on-speed-the-plow-and-mercury-poisoning/11222?nc

Peter MacNicol (2001) · Brad Garrett (2002) · Brad Garrett (2003) · David Hyde Pierce (2004) · Brad Garrett (2005) · Jeremy Piven (2006) · Jeremy Piven (2007) · Jeremy Piven (2008) · Jon Cryer (2009) · Eric Stonestreet (2010)