RIO DE JANEIRO — Ashleigh Johnson stands out from her teammates on the US women’s Water Polo team. She is different from the other 12 members of the team that will defend its gold medal at the Summer Olympics. It’s obvious when you look at the roster profiles.

They all hail from California. She is from Miami. Johnson is a lonely East Coaster, except people from Florida don’t really think of themselves as being from “the East Coast,’’ Johnson politely explained.

Geography aside, Johnson blends in perfectly in the pool, even though she is the first black woman to play for the US women’s team.

“Well, people are going to think what they think. When I’m in the water I just think of myself as another player,’’ said Johnson. “But I definitely want to be in that role where I can be a role model for other black children who love the sport or any children who want to play the sport.

“I just want to play the sport the way I play it, and be a good representation of how the sport is played.’’

USA Water Polo isn’t just hoping that the 21-year-old Johnson, a dynamic goalie with a sui generis style, will help the Americans strike gold in Rio. They hope she can expand the pool of athletes who are willing to jump into the pool and play one of the most physically demanding Olympic sports, a combination of swimming, soccer, basketball, and hockey that tests lungs and wills.

Just typing about the sport makes you tired.

Water polo tends to have a homogeneous look, both demographically and geographically. According to an Associated Press story, 75 percent of USA Water Polo’s approximately 42,000 members live in California.

“I truly know that the way she represents herself, the way she represents her family, the way she represents this team, but most importantly, the way she represents where she comes from is something kids, adults, anyone can draw inspiration from,’’ said teammate Maggie Steffens, the 2012 Olympic MVP.

“Hopefully, it will inspire them to start water polo and love it as much as she does, as much as we do. I know that she has been a great ambassador for the sport.’’

You get the sense the lithe Johnson could be here competing in the Olympic sport of her choice. She would not look out of place walking next to soccer players, basketball players, volleyball players, or swimmers.

The daughter of Jamaican immigrants, Johnson picked up water polo as a child. Her mother, Donna, got a house with a pool and wanted to make sure her five children were safe, so she made them all join a swim club. As part of the program, water polo was offered.

Johnson always preferred water polo to swimming.

As a sophomore at Ransom Everglades High School in Miami, Johnson made a bet with her mother that if she won the 50-meter freestyle Florida state title she could quit swimming and focus solely on water polo. She won the state title and her freedom from competitive swimming.

Johnson was named top goalkeeper at the 2015 FINA World Championship last August after tallying 66 saves in the tournament. She was MVP of the gold-medal match after making 12 saves in a 5-4 victory over the Netherlands.

She attends Princeton, where she majors in psychology and plays on the water polo team with her younger sister Chelsea. Ashleigh took the year off from school to move to the West Coast and prepare for the Olympics with the national team.

Now, the ebullient Johnson is here in Rio as the backstop for a US team that is favored to repeat.

In water polo, there are seven players per side. Only the goalie is allowed to touch the ball with two hands and can do this inside the 5-meter line to defend shots.

The traditional water polo goalie is passive, waiting for shots. That’s not the 6-foot-1-inch Johnson’s style.

The girl her teammates call “A-yay’’ is an attacking goalie.

She starts counterattacks and swats away shots like a whirling windmill at a miniature golf course. She is the water polo version of a Russell-esque rim protector.

USA Water Polo coach Adam Krikorian told Time Magazine that due to her athleticism she “plays the position of goalie unlike anyone has ever played the position before.’’

“I definitely know that I play a little bit different from everyone,’’ said Johnson. “I’m more active as a goalie. Most goalies sit in the cage. I come out and try to make steals. I rely on my athleticism a lot, which was kind of a bad thing early because I wasn’t as technically sound . . . But I’ve worked on my technical skills, and I’m still playing the way I’ve always played. It’s fun.’’

Johnson is an Olympic rookie, but the team has four players who were members of the 2012 gold-medal squad -- Steffens, Melissa Seidemann, Courtney Mathewson, and Kami Craig.

Johnson admits to having some Olympic jitters ahead of the team’s opener Tuesday against Spain, the team the Americans beat for the gold in London in 2012. But she knows her teammates have her back, even if there are some geographical differences in their water polo patois.

At a team meeting, Johnson referred to the defender assigned to guard the center incorrectly. Hilarity ensued. It’s now a somewhat ribald running joke that keeps the team loose.

Not much gets by Johnson in the pool, but she did let an opportunity slip by her at the Opening Ceremony. Johnson and her sister have been called the Serena and Venus Williams of water polo.

The women’s water polo team marched into the Opening Ceremony next to Serena. Johnson was too shy to introduce herself.

“I was kind of really starstruck. I didn’t go say hi,’’ said Johnson, sheepishly. “I didn’t want to overwhelm her or anything because so many people were going up to her.’’

Yo, Serena, when you’re done forehand smashing the competition at the Olympic tennis tournament look up an East Coast girl who would love to meet you.

Christopher L. Gasper can be reached at cgasper@globe.com. Follow him on Twitter @cgasper.