As a boy, Stephen Podgajny didn’t spend his summer days dreaming of being a librarian.

“I was much more concerned with trying to throw a curveball,” said Podgajny, whose father, John, pitched in the major leagues.

But he never quite mastered the curve and, after working in the insurance business, Podgajny became a librarian when he was in his late 20s. He said he wanted a job where he could make a difference.

On Thursday, Podgajny announced that he will retire in 2015 as executive director of the Portland Public Library, after a 36-year career in libraries.

During his eight years on the job in Portland, the library has undergone a $7.3 million renovation that transformed a somewhat drab concrete building into an open, sunny space with a glass facade that’s lit in various colors at night.

The library on Congress Street is now routinely filled with patrons using its 50 computers, reading in nooks or sitting at cafe tables in the front atrium. It also is an anchor of the city’s arts and cultural corridor, with regular art exhibits, programs, and works of art displayed around the building.

Podgajny said one thing he’ll miss most about his job is the feeling he gets whenever he walks through the library door.

“It’s this feeling of what happens to individuals when they come into a library. It’s this step forward people take toward fulfilling their potential,” said Podgajny, who is 63 and lives in Brunswick. “And it happens every day in a public library.”

Podgajny said Thursday that he intends to retire as the library’s executive director as of July 1, 2015. His decision is based partly on his age, he said, and on the fact that he has a son in Montana and would like to spend more time there. He plans to spend time volunteering and “generally supporting civic life.”

The library is privately run, governed by a board of trustees, but gets more than 80 percent of its funding from the city. Podgajny had been talking about his retirement with board members “for a while” before Thursday, said Eric Altholz, president of the board.

Altholz said a search committee of trustees and community members will be formed in the next month or so, and the position will be advertised nationally.

Altholz cites Podgajny’s vision and leadership as key reasons the library was able to raise about $3.3 million for its first major renovation since it opened in 1979. The other $4 million for the project, which was done in 2009 and 2010, was funded with bonds.

Altholz said efforts to raise money to renovate the library had “stalled” several times before Podgajny arrived. Podgajny’s relaxed but passionate way of talking about the importance of libraries helped build support for the project, he said. Podgajny was particularly persuasive while giving “hard hat” tours of the library during renovations.

“He’s a very energetic person, and a very optimistic person,” said Altholz. “He has a passion for the mission of public libraries that is really infectious.”

Altholz said the library still needs renovations that weren’t done in 2009 and 2010, including on the lower level. That will be a main focus for Podgajny’s successor.

“We’d like to get somebody who brings a lot of Steve’s attributes to the job,” Altholz said. “He’ll be a hard act to follow.”

Podgajny was director of the Curtis Memorial Library in Brunswick for 18 years before taking over at Portland’s library in 2006. He also had worked at the Dyer Library in Saco.

During his tenure in Portland, Podgajny has worked with the Maine Historical Society on plans to build a collections storage building that both will use. The center would allow the two institutions to clear space from their main buildings to create more room for programs, exhibits or other things that engage the public.

“He’s not thinking strictly about the Portland Public Library and its interests in isolation. In doing something like this, he’s thinking about the impact on the community,” said Steve Bromage, executive director of the historical society.

Podgajny had some duties he didn’t relish, like presiding over the closing of the library’s Reiche and East End branches to make the remaining four library locations more sustainable.

But after the renovation of the main library, the system drew more visitors than it had before the two branches closed, Podgajny said. It also added a bookmobile, to provide programs and services to city neighborhoods.

When asked, Podgajny said one of his favorite things about the main library is that works of art are now scattered throughout the building. Statues, paintings and sculptures by notable artists are all over the library, not just in the Lewis Gallery, which features changing exhibits.

“I love having art throughout the library as an environmental element,” said Podgajny. “People come to the library for something, and they collide with art.”