Just a few months after being jettisoned by the Indiana Pacers and joining the Golden State Warriors in 2007, Stephen Jackson helped his new team upset the 67-win Dallas Mavericks in the opening round of the NBA playoffs. By the beginning of the following season, Jackson had picked up a new nickname to paste over the old troublemaker label that led Indiana to trade him.

Don Nelson, the Warriors’ coach at the time, christened him Captain Jack.

“He was our leader,” Baron Davis, the point guard widely recognized as the best player on that team, said this week of Jackson.

Controversy found Jackson often during his 14 NBA seasons, but teammates as decorated as Davis and retired San Antonio Spurs star Tim Duncan have raved for years about his leadership, loyalty and protective instincts.

Those same qualities have been on display over the past two weeks in Minnesota, where Jackson has stepped back into the public spotlight as an activist in support of George Floyd, his longtime friend from the Houston area who was killed May 25 in Minneapolis while in police custody.

“People have been telling me, ‘Jack, you’re suiting up for your biggest game ever,’ ” Jackson said in a telephone interview. “When I get texts like that, it moves me and excites me.”

Jackson had just awakened from a nap on his couch with his 6-year-old daughter Skylar when he first watched the ghastly video of Floyd’s neck being pinned against the concrete under the knee of a white Minneapolis police officer, Derek Chauvin, for nearly nine minutes. Chauvin has been charged with second-degree murder, and three other officers who did not intervene have been charged with aiding and abetting.

It did not immediately register that the man on the ground gasping for his life was his pal from the Cuney Homes public housing complex in Houston’s Third Ward, until Jackson turned off the video and was besieged by text messages from concerned friends. The screams that followed, Jackson later told the “Today” show, scared his daughter.

Since then, sleep has been scarce for Jackson, who flew to Minnesota determined to tell Floyd’s story and bring more attention to his fate. Jackson wasn’t there long before he had become an unforeseen spokesman for the family and for the larger Black Lives Matter movement that has surged throughout the world.

After days’ worth of public appearances, Instagram posts and television interviews to continue the campaign — including a passionate May 29 speech during a news conference at Minneapolis City Hall — Jackson was in Houston on Tuesday for Floyd’s funeral at the Fountain of Praise church, where he sat near Floyd’s 6-year-old daughter, Gianna.

On Thursday, Jackson was back in Minneapolis for a march on the local district attorney’s office with a specific goal. “I’ve got to stay until we get convictions,” Jackson said, referring to Chauvin and the three other officers charged in Floyd’s death.

Jackson, 42, was introduced to Floyd through a mutual friend in the mid-1990s, before he was selected by the Phoenix Suns with the 42nd overall pick in the 1997 draft. The two bonded immediately over their facial resemblance — they habitually referred to each other as “twin” — and became close enough that Jackson brought Floyd as a guest to Washington in 2001 for the NBA’s All-Star Weekend, where Jackson played in the Rookie Challenge as a member of the New Jersey Nets.

Jackson bounced around before landing with the Nets, playing in professional leagues in Australia, Venezuela and the Dominican Republic as well as in the Continental Basketball Association. Through it all, trips to see Floyd in Houston were a staple for Jackson, who furnished him with clothes in later years after Floyd moved to Minneapolis to try to restart his life after multiple arrests and incarcerations.

“Every time I watch that video, I see myself down there because we look so much alike,” Jackson said. “It easily could have been me down there: Just let me get pulled over by an officer who’s having a bad day and don’t like the fact that I’m in a nice car.”

Jackson said he and Floyd were “going down the same road” in their youth, spending time “in the same neighborhoods, in the same cars, doing the same things.”

“But I had more opportunity,” Jackson said. “The reason we need to change how people look at us and put some money into these minority areas is because there’s no opportunity there.”

He added, “If I can stand up for a change in the world and everybody coming together and standing together and making history with protests and knocking some doors down to get social justice and change some of these laws — if the president ain’t going to do it, hey, I’ll stand up and do it.”

Jackson helped Duncan and the Spurs win the second of their five championships in 2003, but he hasn’t been in the national spotlight like this since November 2004, when he followed his Pacers teammate Ron Artest (later known as Metta World Peace) into the stands late in a game at Detroit for a brawl with spectators.

Jackson, who received a 30-game suspension for his involvement, has long maintained that he knew it was wrong to cross the line into the crowd but that he did not see it as an option to leave World Peace, who was suspended for the rest of the season, to fend for himself.

“That’s what I was taught,” Jackson said. “Stand up for your brother and worry about the consequences later.”

A subsequent arrest outside an Indianapolis strip club in October 2006, when he fired a gun into the air in what he described as an act of self-defense, led to a charge of criminal recklessness and a seven-game suspension from the league — and spurred the fed-up Pacers to trade him to Golden State.

He ultimately became known as much for technical fouls and bursts of volatility as for his clutch shotmaking and his stirring run with the Warriors in the second half of the 2006-07 season. Yet Jackson had more fans than detractors throughout his NBA career, which helps explain why few in league circles have been surprised by Jackson’s new calling as a crusader for social justice.

“Some people still connect him with the brawl against the Pistons, which will always happen,” said Matt Barnes, a former NBA player who this season started a podcast with Jackson on Showtime called “All the Smoke.” “But I’m glad that he’s able to really show the world who he is. It wasn’t something that he asked for. It was a situation that was pretty much put on his plate, and I think the leadership he’s demonstrated and the movement he helped create is going to be the beginning of a change not only for the United States but hopefully the world.

“For 400 years,” Barnes added, “we’ve been silently marching and protesting and taking a knee, and that’s fallen upon deaf ears. I think for the first time the world hears us, and Jack has been at the forefront of that movement.”

Jackson, as a result, has received messages and calls of encouragement from an array of NBA luminaries, including LeBron James, Chris Paul and Commissioner Adam Silver. Some of the most uplifting support, Jackson said, came from Warriors coach Steve Kerr, his former Spurs teammate, and Minnesota Timberwolves coach Ryan Saunders.

“To have two white coaches reach out,” Jackson said of Kerr and Saunders, “that meant the world to me.”

Yet no conversation has stayed with Jackson as much as the one he had with Hardel Sherrell’s mother on his first day in Minneapolis last month. Sherrell died in the Beltrami County jail in Minnesota in 2018 despite complaining of his deteriorating health. Sherrell’s mother, Del Shea Perry, has maintained that her son’s symptoms were ignored for days before his death.

“She was outside crying by herself as we were walking to our protest,” Jackson said. “Every time I speak now, I try to bring a light to her son’s death because her son doesn’t have a Stephen Jackson as a friend. I’m embracing being a voice for the voiceless.”

It was Nelson, the winningest coach in NBA regular-season history, who officially made Jackson a team captain for the first time at the start of his eighth NBA season in 2007-08. To Davis, the two-time All-Star guard, Captain Jack is a natural.

“Stephen Jackson has always been outspoken and leads with his heart,” Davis said. “I think the Stephen Jackson that you’re seeing now shows the progress that one can make and not only know how to lead with his heart but also with his mind.”