December 1991: Named exec producer of slumping “Today.” After bringing in Katie Couric and adding segments like a concert series, “Today” shoots back to No. 1 among morning shows, where it remains.

December 2000: Appointed NBC Entertainment prexy.

February 2001: Convinces the producers of “Friends” to add 10 minutes to February sweeps episodes, creating “supersize” editions.

September 2001: “Emeril” debuts.

October 2001: “Emeril” is pulled.

December 2002: The “Friends” cast agrees to stick around for one more year; Zucker manages to keep the Thursday night lights on — for a little bit. But it’s one of several Hail Mary moves Zucker makes over the years to delay the bleeding.

December 2003: Zucker begins his executive ascent, taking on oversight of news, broadcast and cable at the Peacock.

January 2004: Gives “The Apprentice” the plum Thursday 9 p.m. slot, effectively ending the era of “Must See TV” and ceding ground to rivals on scripted programming.

May 2004: Zucker’s portfolio expands with the completion of NBC’s acquisition of Universal Studios.

September 2004: Jay Leno and Conan O’Brien agree to Zucker’s plan to transition O’Brien to host of “The Tonight Show” in 2009.

May 2005: NBC ends the 2004-05 TV season in fourth place in the adults 18-49 demo, marketing the first time it’s come in last among the Big 4 nets.

December 2005: Named CEO of NBC Universal TV group, setting him up as the successor to NBC Universal CEO Bob Wright .

October 2006: Proclaims the end of scripted programming in NBC’s 8 p.m. slot as part of the “NBC 2.0” budget-cutting plan.

February 2007: Named prexy and CEO of NBC Universal following Wright’s retirement.

May 2007: Hires agent-turned-producer Ben Silverman to head NBC Entertainment, forcing out Kevin Reilly, who relocates to Fox.

January 2008: Proclaims that NBC will cut costs by no longer producing as many pilots in favor of straight-to-series orders.

December 2008: Announces plan to keep Jay Leno at NBC with a nightly 10 p.m. variety show.

September 2009: “The Jay Leno Show” opens big but quickly settles into fourth place.

December 2009: General Electric reaches deal to sell 51% stake in NBC Universal to Comcast Corp.

January 2010: “Jay Leno Show” is axed amid a revolt from NBC affiliate stations over low ratings leading into late newscasts. NBC returns Leno to the 11:35 p.m. time slot, spurring O’Brien’s departure.

September 2010: Zucker announces his departure from NBC.