He replaces David Rojas, who led the Tornadoes to a 2-14-1 record with a 2-11-1 mark in the Pacific League for seventh place last season.
Kennedy, a native of Dublin, who is an English teacher at Hoover, coached the Tustin High boys' squad the past two seasons.
"Coming from Tustin, it was definitely a hotbed," said Kennedy, who took over the program in late August. "Our teams did well and we were able to build a program that was competitive.
"I've never coached a [high school] girls team before. It's eye-opening and their work ethic has been fantastic. It's definitely going to be a project, but there's potential."
Hoover didn't qualify for the playoffs last season in a league that features Crescenta Valley, Arcadia and Burbank. Crescenta Valley won the league championship last season.
Kennedy, one of five first-year area girls' coaches, said he'll work with the current group of players and try to put the Tornadoes in position to post a winning record and stay in contention for a playoff berth.
"There's an opportunity to do well," Kennedy said. "The practices have been going well. We'll also have a longer preseason [schedule] that will help us get ready for league. In the past, Hoover went into league cold."
Hoover Athletic Director Jack Van Patten said Kennedy has the credentials to turn around the Tornadoes.
"His résumé was impressive and he's an expert at soccer," Van Patten said. "He's got an outstanding personality and he came highly recommended.
"We are lucky to get him and he's a gain for us with a guy of his caliber. He's perfect for us and the girls are responding to him."
Joining Kennedy as first-year coaches are Jorden Schulz at Crescenta Valley, Victor Aquino at Glendale, Basile Pagourtzis at Holy Family and Lemar Sandiford at Glendale Adventist Academy.
Glendale Adventist will be a first-year program.