Maura Tierney was originally cast as Sarah. NBC moved the show's originally slated fall release to mid-season, when Tierney was diagnosed with breast cancer. Due to her cancer treatment, she eventually had to leave the show and Lauren Graham replaced her.
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.
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".
Vanessa Marano makes a guest appearance on Parenthood. Lauren Graham and Vanessa previously worked together on Gilmore Girls. Peter Krause and Vanessa also previously worked together on Six Feet Under.
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, a photo Hank took which she finds amazing. In actuality, this photo was taken by world-famous photographer Steve McCurry from the inside of a taxi on one of his many voyages abroad.