"It's a very special moment for me," he said. "I couldn't ask for a better situation."
He spoke about coming to grips with his situation and the steps he has taken not only to become a better person but to be a role model who can break down stigmas attached to mental illnesses. More than general manager Phil Emery or coach Lovie Smith have, Marshall, 27, admitted the Bears are taking a risk with a player who has been suspended once before for violating the NFL's personal conduct policy.
"From perception? Yes," Marshall said. "From the things I've been through? Yes. From the reality of it? Yes, absolutely."
The trade -- the Bears shipped the Dolphins the third-round pick they received from the Panthers in the Greg Olsen trade (74th overall) and their 2013 third-rounder -- will be a masterstroke for the newly hired Emery if Marshall stays out of trouble. He was second in the NFL in receptions over the last five seasons and has a connection with quarterback Jay Cutler. If it backfires, it will be a failure rooted somewhere between arrogance and desperation for a club that has been starved for a big, productive receiver.
Marshall's history of off-field problems is long, with a pattern of being accused of violence against women, most recently Sunday in New York where a 24-year-old woman alleges he punched her in the eye outside a club. He maintained his innocence and praised how attorney Harvey Steinberg is handling the matter.
He was adamant when asked if he is concerned the NFL will suspend him again.
"Absolutely not," Marshall said. "No fear at all. Once it has taken its course you'll see things totally different. I understand and I get the perception out there. Those are the seeds that I planted early in my career up until last year. I've been here before. But this time it's a little different."
The woman who claims Marshall gave her a black eye met with the New York police Thursday with her high-profile attorney, Sanford Rubenstein.
"My eye still hurts," Christen Myles told the New York Daily News. "I still have problems with my vision. I want him held criminally accountable for what he did to me."
Cutler showed up to lend support for Marshall, whom he hooked up with successfully for the Broncos in 2007 and '08. It was the first time he had been made available since his broken right thumb ended his season six games prematurely and the Bears season spiraled out of control, leading to a front office shake-up.
"In my time here, I think anyone that has listened to me knows I've petitioned to get Brandon here," Cutler said.
If Marshall can deliver on his promises, it will be a wonderful pairing. His foundation and website, projectborderline.com, are dedicated to making an impact.
"Just going back the past six years and seeing how things played out in my life and how devastating at times things have been, the turmoil on and off the field really hit home with me," Marshall said.
"A lot of people are afraid to talk about it. It's a taboo topic in our communities and I'm willing to use myself, make myself and my family vulnerable, to break the stigmas. For me to go through the treatment that I went through last offseason -- to see the change in myself and to have that feeling of wow, now I can live a healthy and effective life -- it was an amazing experience.
"I'm in a position where I'm healthy and I want to be one of the faces, one of the pioneers for breaking the stigma on mental illness and borderline personality disorder. It's one of the most devastating disorders out there, but it's the most treatable. I'm excited. I think the community will see us and feel what we're trying to do."
How does Cutler view his friend now that they are reunited?
"He probably has his stuff together more than 90 percent of this room," he said. "He said anyone needs therapy. I talk to a lady. I go to therapy. I don't suffer from borderline personality disorder, but it's always good to talk to somebody, get different perspectives. I'm happy for him. He seems to be in a good place in his life and moving forward. It's going to be fun."
Imagine what kind of therapy a Super Bowl will be for Bears fans if this works.