By: Elowen Gray
When Michael Sullivan left the Internal Revenue Service in 1982, it wasn’t just the end of a federal career but the beginning of a private-sector revolution in tax resolution. Having spent a decade on the frontlines of enforcement, tackling everything from narcotics trafficking to high-dollar tax evasion, Sullivan shifted from government agent to taxpayer advocate, bringing insider knowledge and field experience to a complex, often intimidating profession.
Over the next several decades, Sullivan became one of South Florida’s most trusted tax resolution specialists. His transition from federal revenue officer to founder of MD Sullivan LLC is known for its personal triumphs and redefining tax representation in the region.
After resigning from the IRS following a tragic personal event (his wife being shot during a bank robbery), Sullivan took time to regroup. He realized his passion for tax work hadn’t faded but simply evolved. He decided to use his knowledge for a different purpose: helping individuals and businesses fight back when facing the full weight of IRS enforcement.
The transition wasn’t easy, but it was purposeful. Sullivan partnered with a few like-minded professionals to form a tax resolution firm. From the start, his approach was different. He knew the system, the agents, the procedures, and most importantly, he understood how cases could go off the rails if clients didn’t have experienced representation.
It didn’t take long for word to spread. Sullivan’s ability to interpret complex IRS codes, negotiate settlements, and preempt aggressive collection actions earned him a strong reputation among attorneys, CPAs, and desperate clients who didn’t know where to turn.
Operating out of premium office spaces (often in penthouses of reputable bank buildings), he was a symbol of professionalism and authority in a field riddled with misinformation and fear. Over time, he built a reputation as a practitioner and a thought leader in tax resolution.
As his practice upscaled, Sullivan took the initiative to earn formal recognition. He was certified by the Florida Department of Professional Regulation to teach courses in IRS tax resolution. Additionally, he was granted a Florida Bar teaching number, an honor given to very few non-attorneys, which allowed him to provide continuing legal education (CLE) for tax attorneys.
Next, Sullivan served on the Greater South Florida Tax Counsel and was appointed Vice President, where he coordinated forums between the IRS and practitioners. These events became educational hubs, drawing hundreds of professionals seeking updates on tax law, compliance tactics, and policy shifts directly from experts in the field.
Eventually, Sullivan established his own firm, “MD Sullivan LLC,” and positioned it as a nationwide tax resolution powerhouse. Clients from across the United States began seeking his representation, from working-class families to celebrities and high-net-worth individuals.
Sullivan’s firm specializes in Offer in Compromise (OIC), installment agreements, currently-not-collectible statuses, trust fund recovery penalties, and complex audit defense. With over 10,000 cases under his belt, he is regarded as one of the nation’s foremost experts in IRS tax relief.
With the rise of social media, Sullivan recognized the need for a professional community, a safe space where tax experts could learn, collaborate, and support one another. So, he founded The Tax Mob, a private Facebook group exclusively for CPAs, enrolled agents, tax attorneys, and former IRS agents.
What started as a modest initiative has grown into a thriving digital think tank of over 5,300 members. Group discussions range from case strategy to legal updates, offering practitioners a platform for peer review, mentorship, and networking. The Tax Mob group holds annual conventions in destinations like Las Vegas, Nashville, Denver, and Puerto Rico, allowing members to connect face-to-face and sharpen their skills in immersive, IRS-centric conferences.
Sullivan’s passion for education has defined much of his post-IRS life. As a certified instructor, he has taught hundreds of new agents and private practitioners the complexities of federal tax resolution. He was also instrumental in training IRS agents in Atlanta, where he became a certified teaching instructor.
Many of today’s most successful tax resolution specialists trace their early training or inspiration back to Sullivan. He has mentored scores of professionals, and his influence continues to ripple through the field.
He also maintains a successful YouTube channel, “Help from a Former IRS Agent,” which boasts over 1.7 million views and nearly 3,000 subscribers. His videos provide free guidance on IRS procedures, taxpayer rights, and real-world strategies, making his expertise accessible to everyone.
What makes MD Sullivan’s story so compelling isn’t just his accomplishments but the total arc. From blue-collar beginnings in Detroit to elite government service, he’s never stopped building. And while his resume includes DEA collaborations, IRS seizure units, national media appearances, and Facebook group empires, Sullivan’s true legacy lies in empowering others, both professionals and taxpayers alike.
