Sen. Darline Graham said Monday she will run for a full six-year Senate term in the South Carolina special primary on Aug. 11.
"I've made a decision," Graham told Fox News. "I'm in."
She was sworn in last week after Gov. Henry McMaster appointed her to serve out the remainder of her brother's term, which runs through early January.
Graham, 62, does not have a background in elected office and worked in disabilities services, most recently as commissioner of the South Carolina Commission for the Blind.
The late senator had secured the GOP nomination in June for what would have been his fifth term representing South Carolina and died July 11.
Republicans seeking the seat may file between July 21 and July 28; the special primary is Aug. 11, and if no candidate secures a majority a runoff will be held on Aug. 25. The winner will face Democrat Annie Andrews in November.
President Donald Trump publicly encouraged Graham to run after meeting with her at the White House and wrote on Truth Social that she would have his "Complete and Total Endorsement" and, "I hope Darline does this, in that there would be nobody better to honor the legacy of her beloved brother, Lindsey," Trump wrote.
Other Republicans who have announced bids include Rep. Ralph Norman, who announced on Saturday, Rep. Russell Fry, who announced on Monday, and businessman Mark Lynch, who lost to Lindsey Graham in the June Republican primary.
When she accepted the appointment, Graham said finishing her brother's term "is what Lindsey would have wanted," and that she planned to "honor him in this way." She also said, "Lindsey has always been there for me, and now I will be there for him."
Funeral services for Lindsey Graham are scheduled for July 28 in Washington, D.C., and July 29 in South Carolina.