Steve and Lynda Weiss said that when they first stopped by Rock City Church, it felt a little strange. After all, not every church holds its Sunday worship services in a movie theater.

Steve and Lynda Weiss said that when they first stopped by Rock City Church, it felt a little strange.

After all, not every church holds its Sunday worship services in a movie theater.

But they were warmly greeted when they walked through the doors, and the music of a praise band inspired them to worship God.

“It only took us a minute ... to feel very comfortable,” Mr. Weiss said. “It just grabbed us from the beginning. We were definitely hooked after that first experience.”

Membership in Rock City, which meets in the AMC theater at Lennox Town Center on the Northwest Side, has grown from about 400 people when it launched in April 2011 to about 1,200 people this year.

The church is set to start services in a second theater on Sunday — the Regal cinema at Georgesville Square on the Far West Side.

The Rev. Chad Fisher, pastor, said he and wife Katie started Rock City with backing from the Association of Related Churches. A startup team spread the word largely by reaching out to neighbors, Mr. Fisher said.

“We just talked about the idea of starting a church that really engaged the spiritually restless and the unchurched,” he said. “A lot of people who attend Rock City have either never been to church or they’ve not been to church in many years.”

This year, the church was ranked 17th on a list of 100 fastest-growing evangelical Protestant churches compiled by Outreach Magazine. Rock City grew by about 570 attendees from 2012, a 130 percent increase, based on figures reported by the church to LifeWay Research, which compiled the list.

The Fishers were ministering at a church in Toledo when they decided to follow their dream of “ helping people afraid to walk through the doors of a church,” Mr. Fisher said.

He said the bulk of his congregation is made up of young professionals, college students and young families, but the church attracts a wide range of ages. They’re drawn, in part, by Rock City’s generosity, he said.

The church holds community events, such as Laundry Love, in which members gather at a laundromat to wash clothing for those in the community who need that service. It also works with an elementary school to give shoes and backpacks to children, and has worked with an organization to help a church in San Salvador build a clinic to provide meals, education, spirituality and medical care for children.

“There’s something that’s telling people, ‘We need to do more,’ ” Fisher said. “We feel we’re really striking a chord there, giving people an opportunity to get in the game and make a difference.”

That’s the reason Kim and Billy Klopfer, then in their 30s, left another nondenominational church to attend Rock City. They serve as ushers, volunteer during service projects and are members of a prayer group.

“My wife and I wanted to be involved with a church that was making an impact in the community we live in, which is Downtown,” Mr. Klopfer said. “They are a very giving church.”

He said they also are impressed with Fisher’s passion for reaching those without a church and with how Rock City uses branding and social media to attract young people who might never have considered worship.

The Weisses, who are in their 50s, also say they were attracted by Rock City’s focus on serving others. And, Mr. Weiss said, Fisher’s sermons are direct, helpful in day-to-day life and keep him on the edge of his seat.

The Dublin couple started attending Rock City after nearly two decades at a Methodist church that they felt had started to stagnate.

“I think what it came down to was our faith evolved to the point where we thought there should be more to church,” he said. “We just thought that God was calling us to do something else.”