First, vacation time should be over for his Charlotte Bobcats teammates now that they're in perhaps the most powerful division in the league.
Second, don't crown the Heat champions just yet.
"They're going to be great," Jackson said. "It's going to be good for basketball. It's going to be good for the city of Miami. It's going to be exciting for the game. At the same time, they've got to go out there and win games just like every other team."
While he thinks James should have signed with Chicago or stayed in Cleveland and "showed a little more loyalty," Jackson isn't backing down from the challenge of being in the same Southeast Division as a now-stacked Heat team that also includes Dwyane Wade and Chris Bosh.
"I'm not one of those guys who's going to lay down just because they put all those guys on the same team," Jackson said. "I don't think anybody on my team is going to lay down. We're going to come out and play. Everybody has respect for those guys, but at the same time you have to win games to get respect on the court."
So far the Michael Jordan-owned Bobcats have lost ground in what's been a league-altering week of free agency. While Charlotte is hamstrung from making a splash because of salary-cap woes, its rivals have made giant moves.
None is bigger than what the Heat accomplished. The team that was fighting for playoff positioning with Charlotte late last season re-signed Wade, got Bosh and then were the winner in the LeBron sweepstakes when the two-time league MVP announced Thursday night he was deserting the Cavaliers.
"If I were LeBron, I would have gone to Chicago or I would have stayed home and showed a little more loyalty to my city and my team," Jackson said. "But I'm not LeBron. That's the best decision for him and everybody has to live with it."
That's when a defiant streak kicked in for Jackson after he mingled with kids at Jordan's fantasy basketball camp at Time Warner Cable Arena. After averaging a team-best 21.1 points last season and leading the Bobcats to their first playoff berth, Jackson isn't ready to slip into the background in a division that also includes Dwight Howard and Orlando, Atlanta with Joe Johnson and Washington with rookie John Wall and Gilbert Arenas returning.
"I love it," Jackson said. "This is what I play for, to overcome odds. ... If you think you can just wait until September to get ready? You've got to start getting ready now."
The Bobcats team that begins next season is likely to have a different look despite coming to terms with restricted free agent forward Tyrus Thomas on a five-year, $40 million deal Friday.
"We're still trying to shake our roster up," general manager Rod Higgins said.
No matter what they look like, they'll face a task four times a year that few could have envisioned: James, Wade and Bosh on the same team.
"The feeling of knowing that they're stacking this team and we still have the ability to go out there and beat them, I think that's something that I'm working for," Jackson said. "I think individual defense comes into play a lot now that you have those three great one-on-one guys on the team, great playmakers on the team.
"Saying all that, it can be done. They're definitely still beatable."
ESPN.com's Chris Sheridan and The Associated Press contributed to this report.