Minutes later, Arizona Gov. Doug Ducey congratulated Kyl on the appointment via Twitter.
Just as Barack Obama, George Bush and Bill Clinton came together to laud the late Arizonan senator, the notably absent president hit up a golf course in Virginia. Most recently he's been helping President Donald Trump's Supreme Court pick, Brett Kavanaugh, get nominated.
"Now Senator Kyl can cast a vote for Kavanaugh's confirmation", Mr. Ducey said.
During his time back in the Senate, Kyl will have the opportunity to vote on several issues that have been involved in his lobbying activities, from immigration to national security. By picking a "caretaker" replacement - i.e., someone who would not seek reelection in 2020 - Ducey could avoid alienating either contingent, and allow Republican primary voters a chance to choose the seat's long-term occupant. On Tuesday, Arizona governor Doug Ducey made a decision to return the 76-year-old Republican to the Senate, in a move that will strengthen Mitch McConnell's caucus in the short term - but just might weaken it in the long run.
Ahead of a public news conference, Ducey tweeted: "I am deeply grateful to Senator Kyl for agreeing to succeed his friend and colleague of so many years".
Many wondered whether Ducey might appoint a member of McCain's family, either his wife, Cindy, or daughter, Meghan, to take his seat.
Kyl retired in 2012 after a lengthy career in the Senate. Add John McCain as an interest to stay up to date on the latest John McCain news, video, and analysis from ABC News.
If that scenario really happens, one can probably expect even more volatility and confrontation not only in U.S. politics, but also in global diplomacy in the coming days as well.
Kyl has not committed to serving in 2019 and 2020, and he told reporters on Tuesday that he is not interested in running for the seat in 2020.
But after his fighter jet was shot down over Vietnam, leaving him with lifelong injuries, he ultimately left the military and turned to politics, representing Arizona in the US Congress for 35 years.
Kyl, 76, served alongside McCain for three terms and was the second-ranking Republican in the Senate before his retirement in 2012.
At the time, Kyl said, "There comes a time when you have to consider other things".