Gyllenhaal's next long-term relationship was with actress Reese Witherspoon. According to People, the two were already acquaintances, as Gyllenhaal used to work out with Witherspoon's ex-husband, Ryan Phillippe. However, their relationship heated up while filming the 2007 film "Rendition," with a source close to the actress telling People, "Jake went and reintroduced himself to Reese . . . Things slowly progressed, but it was never something she thought would happen from the start. She just kind of developed this little crush over time."
In October 2008, Witherspoon talked about her new boyfriend in an interview with Vogue (via E! News), saying, "He's very supportive . . . Suffice it to say, I'm very happy in life, and I'm very lucky to have a lot of really supportive people around me who care very much for me, and that's all you can hope for in life."
Gyllenhaal and Witherspoon were regularly spotted together throughout their relationship and often as a family with her kids. The pair continued dating until their split in November 2009. According to People, their breakup was partially because Gyllenhaal wanted to get married, while Witherspoon was more apprehensive about tying the knot after her divorce from Phillippe. A source told the publication, "Reese was the one who had to do it. She just got out of a divorce and was so concerned with her family, she just didn't have the time for him . . . "
Despite reportedly being dumped by Witherspoon, Gyllenhaal has spoken highly of her since their split, telling Entertainment Weekly in 2016, "She is . . . one of the smartest, strongest people I've ever met."