Koppelman was born on April 27, 1966 in Roslyn Harbor, New York to a Jewish family, the son of Brenda "Bunny" and Charles Koppelman. His father was a Producer and media executive. Koppelman holds degrees from Tufts University and Fordham University School of Law.

In 1992, Koppelman married Novelist Amy Levine at the Central Synagogue in Manhattan. His sister is Jennifer Koppelman Hutt, who hosts a Sirius Satellite Radio show called Just Jenny. Regarding religion, Koppelman describes himself as culturally Jewish, but from a philosophical standpoint he identifies himself as an atheist. Koppelman is a fan of the Knicks, Jets, and Yankees.

In 1997, Koppelman wrote the original screenplay for Rounders with his writing partner, David Levien. Koppelman has described his approach to writing as a team as having only one rule: no video games in the office. In 2001, Koppelman wrote, produced, and directed his first film, Knockaround Guys, which film critic Roger Ebert gave 3 out of 4 stars. Since then, Koppelman has worked on a dozen films including having written Ocean’s Thirteen and directed an ESPN 30 for 30 documentary, This Is What They Want.

In 2009, Koppelman co-directed Solitary Man starring Michael Douglas. The film was included in both A. O. Scott's The New York Times "Year End Best" list, Roger Ebert's "Year End Best" list, and holds a "Fresh" rating of 81% at the review aggregator website Rotten Tomatoes.

In 2013, Tufts University awarded Koppelman their P.T. Barnum Award for success in Media/Arts. In 2014, Koppelman won an Emmy Award for his 30 for 30 documentary.

Koppelman was a contributor and Essayist at Grantland.com, a website that was dedicated to Sports and pop culture. Additionally, since March 2014, Koppelman has hosted a weekly podcast, "The Moment", on ESPN Radio. In October, 2013, Koppelman received significant media attention for releasing a series of videos on the platform Vine in which he gives screenwriting advice in six seconds or less called "Six Second Screenwriting Lessons". His "Screenwriting, in Six Seconds or Less" Vine from July 31, 2014, generated over 15 million loops in less than nine days. He has also written a short story, "Wednesday is Viktor's", for the anthology Dark City Lights: New York Stories (Have a NYC), published in 2015.

Of his five-year practice of Transcendental Meditation Koppelman said in 2016: "For me it was a way to control anxiety, and I found that the physical manifestations of anxiety just dissipated by about 85 or 90 percent ... So that was a gigantic life change, to not feel a fluttering stomach, to not get a stress headache and things like that."

He first started managing local Long Island bands as a teenager. He would also book bands at a local nightclub. Through booking acts, he came into contact with Eddie Murphy and helped arrange Murphy’s first record deal. As a student at Tufts University, he discovered singer Songwriter Tracy Chapman and executive-produced her first album. He was later brought to Giant Records by President Irving Azoff. During his career, Koppelman was an A&R representative for music labels Elektra Records, Giant Records, SBK Records and EMI Records.