Undeclared was Judd Apatow's follow-up series after Freaks and Geeks, which had also been cancelled after one season, but this time the show shifted from a 1980s high school setting to a contemporary early-2000s college setting.

Several actors from Freaks and Geeks, including Seth Rogen and Jason Segel, returned in Undeclared but playing entirely new, different characters.

The unproduced second-season episode 'Lloyd's Rampage' was written with the character Kieran specifically for That '70s Show star Topher Grace, but he never filmed the part due to a dispute between Judd Apatow and That '70s Show co-creator Mark Brazill.

In a planned but unproduced episode called 'Eric's Birthday', Freaks and Geeks star Linda Cardellini was set to play Eric's new girlfriend; at the time, she was actually dating Jason Segel in real life.

When Undeclared first aired on Fox, many episodes were broadcast out of their intended order, which greatly upset creator Judd Apatow.

The original 2005 DVD release presented the episodes in production order rather than the intended story order, a choice Apatow later called a mistake; newer DVD editions restored the correct chronological sequence.

The producers were unable to secure music clearance for about 10 songs used in the series, so those tracks had to be replaced with suitable substitutes for later releases.

Despite lasting only one season, Undeclared developed a cult following and was ranked #16 on Entertainment Weekly's 2012 list of the '25 Best Cult TV Shows from the Past 25 Years'.