In the June 3 field of eight candidates, Conley Ulich finished fourth, receiving 6% of the vote. Shriver, a Santa Monica attorney, finished second behind former state lawmaker Sheila Kuehl.
Shriver would be "the kind of supervisor who will engage, encourage and empower all people in L.A. County to use their voice and their vote to make L.A. County not just good, but great," the Malibu real estate broker said.
Conley Ulich ran a low-key campaign, focusing on the corrupting influence of money in politics.
Shriver has also been endorsed by John Duran, a West Hollywood City Council member who placed third, picking up 16% of the primary vote.
In the Nov. 3 runoff, Shriver faces Kuehl for the Westside and San Fernando Valley seat being vacated by Yaroslavsky due to term limits.
Follow me on Twitter at https://twitter.com/csaillant2