Steele, who served in the State House of Representatives from 2013-2016, is currently leading Fleenor by 16,102 votes, as of 9:52 p.m. Tuesday.
The state legislator threw her hands toward the sky from the lectern, thanking the crowd for their support in her victory speech.
"This was a referendum, we are now a check, we are a check on all of the horrible things that this GOP administration is doing," Steele said. "From D.C. to the capital of this state, we are a check on their anti-women, anti-immigrant and anti-environment agenda."
The former television news and radio anchor served two terms in the House of Representatives before moving to the State Senate.
Steele is thrilled to return to Phoenix to send a message to Governor Doug Ducey, who won reelection earlier in the evening on Tuesday.
"We are going to hold that line right now, and once I get up there, I will work my heart out for you guys, thank you," she said.