Conciliatory messages on social media. Open invitations for coffee. Zoom calls inviting attendees to unload.

Even before she announced her campaign for Senate in Arizona, Kari Lake, a Republican and a favorite of former President Donald J. Trump, has been on a mission to make peace. Her failed bid for governor two years ago was defined by her fervent embrace of Mr. Trump’s false claims of a stolen election, and by her relentless attacks on the party’s establishment figures who criticized her for that dishonesty. But now, looking to wrest a seat from Democrats in a key presidential battleground, Ms. Lake is courting former foes and trying to mend fences.

In addition to her public overtures, Ms. Lake has reached out privately to establishment Republicans in the state in recent months — including some she personally offended — seeking their support. The list includes Doug Ducey and Jan Brewer, two of the state’s former governors; Karrin Taylor Robson and former Representative Matt Salmon, two of her 2022 primary rivals; and Meghan McCain, the daughter of the longtime Arizona senator John McCain, according to six people with knowledge of the outreach, some of whom insisted on anonymity to discuss private interactions. In some cases, Ms. Lake has expressed regrets about her past behavior, one of the people said.

“There was some damage done from that primary that clearly bled into the general election,” said Daniel Scarpinato, a Republican consultant in Arizona who worked as a top aide to Mr. Ducey years ago. “I think you clearly see a genuine effort to bring more Republicans into the fold.”

Ms. Lake, a former television anchor and political newcomer in 2022, conducted a scorched-earth campaign to win the G.O.P. primary for governor. She appealed to Mr. Trump’s supporters by championing his baseless theories of election fraud, while lacerating her opponents. She accused Ms. Robson of “trying to buy the election with her 95-yr-old husband’s millions,” and blasted Mr. Ducey as “do-nothing Ducey.”

Perhaps most critically, she angered the family of Mr. McCain, who died in 2018, by declaring that her political rise “drove a stake through the heart of the McCain machine” and by inviting the voters in the state who admired him to “get the hell out.” The divisiveness caused some Republicans to balk at backing Ms. Lake, even if it meant a Democrat would win.