Dina Marie Ruiz was born in Castro Valley, California, the daughter of Michael Ruiz, who had been adopted by a Portuguese/Puerto Rican couple as an infant, and his wife, Mary Lou Ruiz, who is of English, Irish and German descent. Michael Ruiz's biological father, Marcus Grant, was African American and Native Hawaiian, and his biological mother, Lilian, was Japanese and Hawaiian. Dina grew up in Fremont, California, with her father teaching school in Fresno.
After graduating from Mission San Jose High School in Fremont, she attended several colleges beginning with Ohlone College, a community college in her hometown, in 1983. While a student at Ohlone, she anchored Newsline for Ohlone College Television. She briefly attended Arizona State University in Tempe, and in 1988, graduated from San Francisco State University with a degree in Broadcast Communications.
In 1990, she was hired as a reporter for KNAZ-TV in Flagstaff, Arizona, and eventually became news anchor. About a year later, she was hired at KSBW in the Monterey-Salinas, California market as a news anchor. She retired in 1997. She met Clint Eastwood when she interviewed him for a newscast.
In 1998, as Dina Ruiz Eastwood, she was host of the television show A Quest for Excellence, produced by the California Teachers Association and featuring students, teachers, and administrators and their daily challenges, as well as celebrity interviews.
Beginning February 8, 2011, announced as Dina Ruiz-Eastwood, and billed on-air as Dina Eastwood, she "guest-anchored for KSBW" the 5 p.m. newscast with weeknight anchor Dan Green. She returned to anchor the 5 p.m newscast for two weeks starting November 11, 2013.
Ruiz Eastwood was featured in the San Francisco State University's 2009 "Alumni Hot Shots" list. She is a former co-host of the television show Candid Camera.
She discovered the South African a cappella band Overtone during the filming of her husband's film Invictus. The band then recorded songs that were used in the Malpaso Productions soundtrack.
Eastwood made brief appearances as a reporter in two of her husband's films, True Crime (1999) and Blood Work (2002). In 2012, she played the role of Vanessa Reeve in The Forger alongside her stepson, Scott Eastwood.
Eastwood joined The California Museum for History, Women and the Arts Board of Trustees and is a past chair.
She met actor-director Clint Eastwood in 1992, when she interviewed him for KSBW-TV. As Clint Eastwood recalled in 2007,
[S]he was doing an interview with me…[and] we got along really well and I guess we flirted a little bit because she took the film back to KSBW and one of her associates said, 'You're going to marry him.' Then we were attending a function out at Spanish Bay and [one of the hosts] said, 'Do you mind sitting with Dina Ruiz?' I said, 'No! Not at all!' We ended up holding hands and doing all that kind of nonsense and then we started dating and we’re still dating. ... She's a very forthright kind of person. It's one of those things you can't put your finger on because it's pheromones or something.
They married on March 31, 1996. The couple has one daughter, Morgan Eastwood (born December 12, 1996).
In April 2013, Dina Eastwood entered rehab for depression and anxiety.
In August 2013, she stated that she and Clint Eastwood had been living separately for an undisclosed length of time. Dina Eastwood filed for divorce on October 22, 2013. In her divorce filing she asked for full physical custody of Morgan.
In July 2016, Dina Eastwood married basketball coach Scott Fisher.