Fisher signed with the Thunder for the remainder of the season Wednesday, not quite a week after he was traded to Houston by the Lakers and subsequently bought out of his contract instead of playing with the Rockets.
He picked jersey No. 37, the same as his age, and took a bit of a shot at the Lakers in the process.
"Especially this season, it seemed to be a negative thing that I was 37," Fisher said after scoring five points in 19 minutes in Oklahoma City's 114-91 win over the Los Angeles Clippers.
"So I just wanted to send a message that the Thunder organization and I see it as a positive that I'm a guy that can still help a team be successful and compete for a championship at the age of 37."
Former teammate Kobe Bryant, for his part, said Wednesday night that he will have no problem treating Fisher like a foe on the court.
"Look, we don't get five championships by being sympathetic towards each other and kissing each other's [a--] during the game," Bryant said Wednesday when asked about the Lakers' game against the Thunder next week. "I'm going to demolish him. He understands that. If he switches off on me in the post, there's going to be problems. I'm sure he'll put an elbow right in my back, and that's why we love each other."
The Thunder lost their backup point guard, Eric Maynor, to a season-ending knee injury in January but hadn't made any moves to address the position. All-Star Russell Westbrook had been taking on extra minutes as the starter, with rookie Reggie Jackson taking over as his backup.
Then Fisher became available when the Lakers decided to acquire Ramon Sessions from Cleveland and promote Steve Blake to the starter. Fisher had won five titles alongside Kobe Bryant in two separate stints with the Lakers, with stops in Utah and Golden State in between.
Fisher was due to earn $3.4 million next season under the terms of his contract with the Lakers. But he surrendered all of next season's salary after being traded to Houston last week to secure a buyout from the Rockets and the opportunity to pick a contender to join for the stretch run.
ESPN.com reported Tuesday that Fisher and the Thunder were "very close" on a deal despite a strong pitch from the Heat, who could offer the veteran only the minimum salary. The Thunder have roughly $3 million left of their midlevel exception and thus possessed the ability to outbid Miami by offering a portion of that amount to sign Fisher to a one-year deal.
Fisher was officially placed on waivers at 6 p.m. ET Monday, giving teams under the salary cap 48 hours to claim him. He was owed a little less than $1 million for the rest of this season and had a player option worth $3.4 million for next season.
Fisher's surrender of next season's salary marks the second time in his career that he has left a significant amount of money on the table to facilitate a move he wants. In 2007, Fisher gave up roughly $8 million owed by the Jazz to return to the Lakers -- with whom he began his career alongside Bryant in 1996-97 -- so Fisher's family could be closer to the doctors who were treating his daughter for a rare form of eye cancer.
He had played 13 of his 16 NBA seasons with Los Angeles before getting dealt away at last week's trade deadline.
"I think that I was surprised by it, but since then I've very much realized that it's not so much about what went wrong and why it happened but more so where I'm going next and the next chapter of my life," Fisher said, declining to speak in depth about his divorce with the team until later.
Fisher figures to take over Jackson's backup minutes, although coach Scott Brooks called the 2011 first-round draft pick one of the Thunder's "important pieces going forward." Fisher has averaged 8.7 points and 3.1 assists during his career, and has played in 209 playoff games in 13 trips to the postseason.
"He has winner all over his DNA," Brooks said. "You can never have enough winners in your locker room, and we have a locker room full of them. He just gives us one more winner."
Fisher played with the Lakers when they knocked Oklahoma City out in the first round of the 2010 playoffs on their way to a second straight championship. He said he's always respected the team because he's observed that the players play with energy every single game.
That approach was reinforced when he met with general manager Sam Presti while he was going through the process of clearing waivers and becoming a free agent.
"It's very clear that there's one common goal, and that's to maximize the abilities of every player on the team and try to bring, at some point, a championship to Oklahoma City," Fisher said.
Oklahoma City made room for Fisher by waiving forward Ryan Reid, a second-round pick in 2010 who had played in only five games over the past season and a half.
"He's got great poise, he's got a great basketball IQ, great recognition on both ends of the floor," Presti said of Fisher. "He understands the league; he's a well-regarded corner shooter and someone that we feel like can settle you down and make plays for you throughout the body of the game."
Presti praised Jackson and reserve Royal Ivey for filling Maynor's minutes over the past two months well enough to give Oklahoma City the league's third-best record, behind Miami and Chicago, heading into Wednesday night's game against the Los Angeles Clippers.
"We have a lot of confidence in the group that we have in place, obviously, to be where we are right now," Presti said. "We know we can improve. ... We feel like Derek's someone that can help enhance where we are currently."
Two-time scoring champion Kevin Durant endorsed Fisher's arrival even before he had officially signed and envisioned him as a mentor to the young team who's still able to hit clutch shots and defend. He was hesitant to look forward and assess Fisher's impact on the Thunder's championship hopes.
"You can ask as many questions as you want, but it's a little different if you go through it yourself," Durant said. "I'm just going to just try to pick his brain as much as I can about the game of basketball, but at the same time, of course if I want to get to that goal, I'll have to experience it myself."
Fisher, in a statement issued Wednesday, thanked fans, friends and family, as well as the Lakers' players for their support.
"To Kobe, Pau, Andrew, Matt, Steve, Devin, Darius, Josh, Drew, Troy, Metta, Luke, and Jason, and all my teammates in Los Angeles through the years, thank you for your friendship, for the camaraderie, for pushing me each and every day to achieve greatness and letting me lead you the best way I knew how. You each have a lifelong friend and supporter in me," he said.
Bryant, who said he has maintained daily contact with Fisher since the 37-year-old guard was traded to the Rockets last week, was not surprised where Fisher ended up after clearing waivers.
"I expected that," Bryant said after the Lakers' 109-93 win over the Dallas Mavericks. "The Thunder needed him, in terms of having a backup point guard who brings a lot of stability and obviously veteran leadership and an ability to make big shots. I could see that coming."
Lakers coach Mike Brown said he was happy Fisher joined a championship contender.
"It's great," Brown said before the Lakers played the Dallas Mavericks on Wednesday. "It's great. You're happy for him and his family because you know he's a winner and that's probably where he wanted to go to, a winning organization, so he'll be able to help those guys out."
Information from ESPN.com's Marc Stein, ESPNLosAngeles.com's Dave McMenamin and The Associated Press was used in this report.