CAÑON CITY, Colo – Rick Raemisch, Colorado’s new chief of corrections, has been in his job for just over seven months. His predecessor was shot to death a year ago Tuesday by a former inmate who had spent years in solitary confinement. During that time, Raemisch has gained a reputation as an outspoken reformer and has made clear that he wants to make significant changes in the way the state operates its prisons.

On Jan. 23, two corrections officers escorted Raemisch to a cell, removed his handcuffs and leg shackles, and slammed the door shut. His 20-hour stay in solitary drew local and national headlines.

On Capitol Hill, where Raemisch told a Senate subcommittee last month that solitary confinement was “overused, misused and abused,” he was besieged by well-wishers, including representatives of the American Civil Liberties Union. Others called his action a politically motivated stunt.

In the last two years, an increasing number of states, prodded by lawsuits, lower budgets and public opinion, have been rethinking solitary confinement, the practice of locking prisoners alone in cells for 22 or more hours a day over a period of months, years or even decades.

Tom Clements, Colorado’s previous executive director of corrections, believed many inmates in segregation cells did not need to be there. He was particularly worried about the state’s habit of releasing some prisoners from long-term isolation onto the streets with no transition. Clements’ killer, Evan S. Ebel, who died in a shootout later with the police, was one such prisoner.

To Raemisch, who was secretary of corrections in Wisconsin until newly elected Gov. Scott Walker moved him out of the post in 2011, the potential negative effects seemed obvious.

“You don’t have to spend much time in a prison talking to someone in a segregation cell to realize that something is inherently wrong with that,” he said, sitting one recent afternoon in his office in Colorado Springs, where photographs show him as a young narcotics detective standing next to giant marijuana plants and with a mountain lion he bagged on a hunting trip in Idaho. “Everything you know about treating human beings, that’s not the way to do it.”

Clements had cut the number of inmates in solitary confinement in half, to 726 from about 1,500. Raemisch has decreased that number to 577, and he has moved all but a few inmates with serious mental illnesses into other settings.

Raemisch emphasizes that 97 percent of inmates will eventually be released.

“It’s our job to get them prepared and determined to be law-abiding citizens when they go back,” he said. “I don’t want any new victims.”

He has also pushed into territory where few others have ventured. A memo sent to corrections staff described an ambitious agenda, including allowing death row prisoners out of their cells for four hours a day and sending inmates to solitary confinement for specific lengths of time instead of indefinite periods.

He hopes to go further, making changes in the training of corrections officers, the preparation inmates receive before they are released and the way that corrections officers interact with inmates.