Clementa C. Pinckney hardly ever took off his suit jacket.

On Wednesday morning, dressed as sharp as always in a dark suit, the rising star in South Carolina’s political and pastoral worlds walked past the coat rack in the corner of his suite in Columbia’s Marion Gressett office building. Sitting at his desk with his back to a view of the Capitol dome towering over a Confederate flag and statue of former Senator Strom Thurmond, Mr. Pinckney prepared for that morning’s finance committee meeting.

Surrounded by framed newspaper spreads (“Leading from the Pulpit” “Under 30 and on the Move”), recognitions of achievement (“Prestigious Jaguar Award, Jasper County High School, 1991”) volumes of bibles and a poster of Martin Luther King Jr., he grabbed a water bottle from a refrigerator bearing a “Yes! I Love My Library” sticker given to him by his wife, Jennifer, a librarian. He set aside a bunch of rolled up posters depicting African-American life in the South Carolina Lowcountry. He planned to take them home that day.

But first, another day of work. Mr. Pinckney, elected to the House at age 23, had always had a sense of purpose. In the seventh grade, the skinny student endured the taunts of his classmates in Jasper County, a depressed angle of the so-called Forgotten Triangle, by wearing a starched shirt and tie and carrying a briefcase instead of a backpack. He thought you needed to dress like someone to be someone.

He quickly became someone. Preaching sermons as a teenager he went on to be a pastor of one of the state’s most historic black churches. An ambitious intern unafraid to ask his bosses to look at the county budget, he became a page in the state House of Representatives and ultimately a member and a senator.

Now he walked by a plate commemorating Barack Obama’s inauguration and took the elevator down to room 105 for another meeting on the budget, where he again advocated, in the face of an overwhelming Republican majority, for funding to fix the roads in his deprived district. The meeting broke and Mr. Pinckney went back up to the fifth floor for an 11 a.m. Democratic caucus meeting. Under pictures of leaping dolphins and portraits of old senators, he was delighted to find a spread of chicken from Grecian Gardens, his favorite local place.

“Oh, we got Grecian gardens! Good job, Antjuan,” he said to Antjuan Seawright, a political adviser to the caucus with whom he also liked to talk about his Jack Victor suits, paisley ties, and their shared new passion for colorful socks.

Mr. Pickney then rose to give a prayer before another strategy session, offering thanks for the gift of fellowship and food and asking the Lord’s guidance.

“That was an AME prayer,” Senator Vincent Sheheen teased him as he sat down, the latest installment in a running joke they shared about the brevity of African Methodist Episcopal prayers compared to Baptist ones. At the end of the meeting, Mr. Sheheen asked his colleagues for a 15-dollar contribution for a gift that the senators planned to give the building custodian. Mr. Pinckney reached into his pocket and pulled out a 20.

Mr. Pinckney and his colleagues were due on the Senate floor for a brief session. He cut through the parking garage, where his new SUV sat in a parking spot bearing his name in white paint. He had run his last car into the ground. He drove dozens of hours every week, to his home down south in Jasper County, to nearby Lexington where he brought his daughters, Eliana and Malana, to school and dance recitals and stayed with his wife in a handsome brick house around the corner from a Christmas tree farm that sat less than 10 minutes away from a yellow single-wide mobile home where an angry young man spent the month spouting hatred against blacks and threatening to do something big. Mr. Pinckney spent that time driving to the State House in Columbia and visiting constituents in Beaufort, Colleton, Hampton and Jasper counties, all of which he represented in the broad swath of southern South Carolina that is district 45.

And he drove it to the historic AME Emanuel church in Charleston where he had become pastor.

He called himself the “itinerant pastor” and his political enemies once challenged his election by questioning the validity of his residence in Jasper County. The challenge failed and he won and now, on another sweltering morning, he rode an escalator up from the parking lot to the State House. He walked between marble columns and up mahogany staircase lined with paintings of the Revolutionary War and greeted friends on a lobby presided over by a statue of John C. Calhoun. In the stately Senate chamber, where chief deputy sergeant-at-arms Charles Williams noted that “time was not an issue with him,” Mr. Pinckney chatted with colleagues on the floor and took a seat next to Mr. Sheheen.

It was here that Mr. Pinckney made his mark.

When Mr. Sheheen nervously prepared to call out his opposition to a compromise reached with Republicans on their effort to introduce a voter ID bill, he was shocked to hear Mr. Pinckney’s booming voice call “No.”

“I knew that when I heard him voting no, loud and clear, I knew I was doing the right thing,” Mr. Sheheen said. They were the only two to vote in dissent.

There was the time when Republican senators mocked his effort to bring a luxury mall to the poor lowcountry, (“who is going to buy Prada in the Corridor of Shame?”) He responded by taking the podium and standing silently for a full minute before saying “Gentlemen, I want to tell you that it is an honor to be able to come to this podium and serve with all of you.” This was the place he advocated for Medicaid expansion and where, in the wake of the killing of Walter Scott, an unarmed man shot in the back by police in North Charleston, he gave a speech that seized the chamber. “You could have heard a rat peeling cotton,” said Mr. Seawright.

But on Wednesday, there were just procedural votes that led to another finance committee meeting on the first floor. Senator Darrell Jackson appealed to Mr. Pinckney, who sat on a health subcommittee, for more funding for a project to help sufferers of sickle-cell disease. “Sickle-cell will be taken care of again this year,” Mr. Pinckney assured him and then added that he wouldn’t be able to stick around for the entire meeting because he had an appointment at his church in Charleston.

It was a place he and Mr. Jackson, the pastor of a large non-denominational church, had talked about often. Mr. Pinckney thought obsessively about how to attract young adults to his historical church in Charleston without upsetting the traditional members or compromising its character. He told Mr. Jackson that he hoped to meet some such promising young congregants that evening.

He climbed back into his car, and waved goodbye to Representative Justin T. Bamberg as he exited the parking lot. About few hours later, he was in the basement of Emanuel A.M.E. Church on Calhoun Street in Charleston, wrapping up yet another budget meeting and certifying new pastors. A smaller group, including one of the young men he hoped would make a future for the church, asked him to stay on for Bible study. As his wife and daughter went upstairs to the pastor’s office, another young man, this one white, this one quiet, came to the door. Dylann Storm Roof, like Mr. Pinckney, spent a lot of time in his car, and he too had driven about two hours to the church. He asked for the minster. Mr. Pinckney welcomed him too and they all sat together around a green table, prayed, sang and then opened to the Gospel of Mark, 4:16–20, which likens the word of God to a seed that must fall on good soil to bear fruit.

Around 9 p.m., 12 hours after Mr. Pinckney started his day in the Capitol, the young white man started shooting. Upstairs, Mr. Pinckney’s wife heard the gunfire and screams. She locked the door, cut the lights, called 911 and hugged her child close. When the police rushed in, they found Mr. Pinckney and eight others in the group dead or dying.

Mr. Pinckney had only one event on his Thursday schedule, a 10 a.m. Senate session back in Columbia, where the Confederate flag still flies. Instead of him hunched over his desk in the chamber’s second row, there is a black cloak and flowers strewn on his chair. Instead of his booming voice bouncing off the walls, a portrait of him will hang. In his office, marked with a wreath of white flowers, the posters that he planned to take home depicting vibrant black life in the South Carolina Lowcountry remain rolled up next to his desk.