Darin Heames played Seth Holt in the pilot but was replaced by John Corbett when the character next appeared in season 2.
Vanessa Marano makes a guest appearance on parenthood, Lauren Graham and Vanessa previously worked together on Gilmore Girls
Maura Tierney was originally cast as Sarah. Initially, NBC moved the show's slated fall release to mid-season, when Tierney was diagnosed to have breast cancer. But, due to her cancer treatment, she eventually had to leave the show and Lauren Graham replaced her.
Mae Whitman and Max Burkholder played siblings on the show "In Treatment", and now play cousins on "Parenthood".
Andrew McMahon of Jack's Mannequin was asked to submit a possible theme song for the series. He ended up writing a song entitled "Casting Lines" but by the time he gave it to the producers they had already settled on using Bob Dylan's Forever Young. "Casting Lines" appears on Jack's Mannequin's third album "People and Things".
The Braverman's are huge baseball fans. Their favorite MLB team is the Oakland Athletics.
In almost every episode, someone makes pancakes or waffles.
Mae Whitman and Miles Heizer are real life roommates
Before Lauren Graham signed on to be Maura Tierney's replacement Helen Hunt was in the running for the role of Sarah, but she and the network failed to reach a salary agreement.
During one scene where Hank asks Sarah to open a drawer for him, she comes across a framed photograph of a rainy window with two people peering through, and it turns out it is a photo Hank took, which she finds amazing. In actuality, this photo is by world-famous photographer Steve McCurry that was taken from the inside of a taxi on one of his many voyages abroad.
Diane Farr was originally cast as Kristina Braverman but had to exit due to scheduling conflicts with Californication (2007).
There is always someone wearing plaid in every scene, even if it's very subtle.
Peter Krause and Lauren Graham are dating in real-life.
When Carl comes to pick up his keys there is a woman with him by the name of Lincoln. Dax Shepard's, Crosby Braverman, first born daughter with Kristen Bell name is Lincoln.
Showrunner Jason Katims, who previously ran the show "Friday Night Lights", cast many "FNL" actors on "Parenthood" in recurring or guest roles, including Michael B. Jordan, Minka Kelly, Matt Lauria, Jeff Rosick, and Angela Rawna.
Lauren Graham was in Bad Santa with John Ritter and played the love interest of John's son Jason Ritter in Parenthood.