Marc obtained substantial results for his clients. He also appeared and prevailed before local and state commissions and the California Court of Appeal. In 2001, he successfully briefed, argued, and obtained a reversal litigating against the largest law firm in the state on behalf of a minority subcontractor on a public works project at the University of California at Berkeley. Holland v. Morse Diesel International, Inc., 86 Cal.App.4^th 1443 (2001).

In 2004, Marc accepted a position with the Fresno County Public Defender to advocate for one of the most fundamental civil rights, liberty. With the approval of the Public Defender, Marc continued to advocate on behalf of his Bay Area clients. While with the Fresno County Public Defender Marc thrived on taking cases to trial that others thought hopeless, further developing his skills at challenging the admissibility of evidence and creating an appellate record.

In 2007, Marc accepted a position in the Fresno office of the Federal Defender for the Eastern District of California. Marc has successfully excluded and suppressed evidence, including state and federal wiretaps. Marc has extensive federal criminal defense experience involving a broad range of crimes, including distribution and manufacture of controlled substances, including synthetic and analog substances; crimes of violence; firearms; bank robbery; racketeering; sex trafficking; internet crimes; sex crimes; child pornography; identity theft; theft; mail and wire fraud; money laundering; structuring; and tax fraud. While at the Federal Defender, Marc merged his skills as a defense attorney, civil rights advocate, litigator, and trial attorney.

In 2015, Marc left the Federal Defender and started the Days Law Firm. The firm has represented clients charged with committing federal and state crimes ranging from murder, racketeering, distribution of controlled substances, offenses for the benefit of a gang, sex trafficking, sex offenses, burglary, money laundering, structuring, tax fraud, mail fraud, embezzlement, theft, firearms offenses, domestic violence, and DUIs.