On Monday, she explained her decision while being introduced at her new job on a video conference.
"I sat in head coaching interviews [in the NBA], and people said two things," Hammon told reporters, per Business Insider's Meredith Cash. "'You've only been in San Antonio, and you've never been a head coach.' ... [The Aces] saw me as a head coach right now."
Hammon, 44, played 16 seasons in the WNBA, making six All-Star teams. After retiring, she joined Gregg Popovich's bench in San Antonio as the NBA's first woman assistant in 2014. She remained there for eight seasons while interviewing for multiple NBA head coaching vacancies, including the Portland Trail Blazers opening filled last offseason by Chauncey Billups. She was not offered any NBA head coach jobs.
When the Aces came calling, she was interested. Though she admitted that she initially "had no intentions of leaving the NBA."
"I never closed the door on the WNBA because I love the WNBA," Hammon said. ... "I've learned to just keep my options open and try to be open-minded. ... When [Aces president] Nikki [Fargas] called, I listened.
"This was not really about the NBA or WNBA, this was about me personally being ready to have a team and wanting to have a team."
She also addressed the obstacles she faced as a woman interviewing for jobs coaching men in the NBA.
"We've never had these conversations about men leading women's teams," she said.
Hammon will finish the NBA season with the Spurs. She'll then inherit an Aces team that posted the WNBA's second-best record (24-8) last season and lost in the playoff semifinals. She replaces Bill Laimbeer, who left his position after coaching the Aces for four seasons. She played her final eight WNBA seasons with the San Antonio Stars, which relocated to Las Vegas in 2018 and became the Aces.
She's kept a close eye on the WNBA during her Spurs tenure.
"To be quite honest, I've been watching the WNBA and stealing their plays for a while," Hammon said.