This summer has thrown Heather Johnson back to her teenage years. She’s living at her parents’ White Bear Lake home, hanging out with old high school friends and soaking up some sun. ¶ And when her parents depart shortly for the New Hampshire Music Festival? Well, keep it on the down low but Heather Johnson’s mom and dad are out of town. Par-tay! ¶ Johnson, 41, is back in her hometown to sing the role of Rosina in Mill City Summer Opera’s “The Barber of Seville,” which opens Saturday in the Mill City ruins along the Mississippi.

This is Mill City’s second summer open-air opera, after last year’s success with “Pagliacci.” The experience must have been great for opera­goers — or they heard about Johnson’s homecoming — because “Barber” nearly sold out 36 hours after tickets went on sale.

“It really is a thrill to come home,” Johnson said during a break in rehearsal. “It’s exciting to be part of this opera company, building it from the ground up and learning as we go.”

As for singing outside, Johnson said she trusts the acoustic of the ruins and appreciates the visceral quality of natural elements such as the twilight playing into the production. The biggest challenge?

“The heat,” she said, like a typical Minnesotan. At least she didn’t say, “It’s the humidity.”

Heather Johnson, who will sing Rosina in “The Barber of Seville,” showed her enthusiasm for a dress design during a costume fitting with Ellen Roeder at Tulle and Dye in St. Paul.

Early music roots

There is a lot of fate in Johnson’s path toward opera. Her father, Joel, was choir director at Roseville High School for 35 years, and her mother, Karen, taught music in the same district. At New Hampshire, he conducts the symphonic chorus, and she accompanies on piano. They’ve been going to the festival since 1963 and Heather remembers the festival’s rare atmosphere as influencing her love of new music.

“I remember sitting next to John Cage, and I just sort of took it for granted that composers were writing new work,” she said.

Johnson studied voice with Dan Dressen at St. Olaf College and then did a tour with young artists at the Minnesota Opera. The troupe went to every corner of the state, doing school and community concerts. The tour is where she discovered that she could sing coloratura.

Johnson has lived in New York for 13 years with her husband, tenor Benjamin Warschawski. They have been wrestling with the work/life balance thing lately, she said (“I’m a workaholic”). Because they both are frequently on the road, they are trying to manage so that they are not apart for more than a couple of weeks at a time.

Her career of late has been on a very positive trajectory (“I’m a late bloomer”) and she made her Met Opera debut this past season. For the next two seasons she is booked solid, which means she is able to make choices about which engagements to accept.

“Do I take a small role at the Met, or a ‘Carmen’ at Virginia or ‘Lizzie Borden’ at Boston Lyric,” she said.

Those are not hypothetical examples. She’s doing “Lizzie” next season in Boston because, “When would I have the chance to do it?” She also likes to do something newer each season.

“It keeps me on my toes and it’s vitally important to keep the art form alive,” she said.

Next April, she will sing “Carmen” at Virginia Opera for director Tazewell Thompson.

“Don’t get me wrong, I love working at the Met,” she said. “I can stay at home, and besides, it’s the Met.”

Mill City connection

Johnson has known Mill City founder Karen Brooks for many years and while they both were at Sarasota Opera (she singing, Brooks in the orchestra), this idea came up. Brooks asked Johnson to serve on her board of directors, and the singer was eager to “see it come to fruition” so she said yes.

Johnson was doing “Madama Butterfly” in Portland last summer, and couldn’t come to “Pagliacci.” For this season, Rossini’s “Barber” is a good follow-up — comic and popular.

Rosina has become one of Johnson’s strong suits. She describes the character as complex, and says she’s never quite sure which Rosina will show up for a particular production.

“I always come in with a clean slate to see what the director wants from the role,” she said. “I never get sick of this opera.”

The barber of seville What: By Rossini. Directed by David Lefkowich, conducted by Brian DeMaris for Mill City Summer Opera. When: 7:30 p.m. Sat. & next Mon., Wed., Fri. Ends July 21. Where: Mill City Museum, 704 S. 2nd St., Mpls. Tickets: Limited availability. $30-$81.50. 612-341-7582, or tickets.mnhs.org.

Johnson still knows her way around town, despite the road construction that has come to define Minnesota summers. One thing that stands out in this visit — her longest to the Twin Cities in many years — is the variety of eateries (“It’s a great foodie town”).

Mostly, though, she’s been content to rehearse the opera and relax.

“It’s such a luxury to be home at the best time of the year,” she said. “The lake comes alive in the summertime.”