On the women's tour, players are already allowed to summon their coaches during changeover once per set, apart from at Grand Slams, and the Women's Tennis Association will trial a new system allowing coaches to interact from the stands.
The trial will start at next week's Dubai Duty Free Championships.
"They should be able to signal from the stands," King told reporters. "Look at baseball. They have a first base coach and a third base coach, the coaches are giving all these signals, squeezing their nose or whatever and making all these signals. It's fascinating for people.
"They make documentaries on these coaches. It's just a story to promote our sport and anything we can do to promote it is a good thing, it's a no-brainer."
The topic of coaching divides opinion and the ATP do not allow it in men's tournaments.
Players can receive code violations for 'coaching' from the stands.
The issue became a hot topic following the 2018 US Open final when Serena Williams's coach Patrick Mouratoglou gestured to the player during her defeat by Japan's Naomi Osaka at Flushing Meadows, leading to a code violation and sparking a heated row between the American great and the chair umpire.
Serena Williams points at the umpire during her US Open final defeat against Naomi Osaka
Image credit: Getty Images
International Tennis Federation chief David Haggerty says he prefers the status-quo as far as on-court coaching is concerned, which is allowed in the Davis Cup and Fed Cup team events where the captain sits on court.
He said the ITF will use data from the WTA Tour trial to revisit the issue.
Twelve-times Grand Slam singles champion King, a trailblazer for the sport throughout her career and afterwards, said tennis needed to get with the times and make coaches part of the narrative, as in other sports.
"I have always been for it (coaching on the court)", the 76-year-old said. "We want more people to go into coaching, and you have to see it to be it. If they are sitting up in the stands no one knows who they are.
"Let's just look at the sports in the United States. They talk about the coaches in college and pro sports as much as they talk about the players. We don't do that for our sport and we are losing out on column inches, and time and media.
"Every coach is a story."
King, one of the toughest competitors the sport has seen, disagrees with those who say allowing coaching mid-match takes away the skill of decision-making from players.
"Yeah, people say in tennis you have to think for yourself, but I've told players countless times what to do and they can either do it or they can't, it's up to them anyway.
"But if we can get more stories, more attention for our sport then I'm all for it."