He's an (in)famous creation evangelist. These days, he's more infamous for being a notable tax fraud. He was convicted in 2006 of around a dozen tax-related crimes and spent some time in prison.
At the time, he claimed that he didn't realize he was breaking the law--which in itself is no excuse for breaking the law--but he was lying; his phone calls from jail were recorded and indicated he knew what he was doing.
He's still lying. Structuring means breaking large money transfers into smaller ones to avoid triggering mandatory reporting requirements. Financial institutions must report cash transactions larger than $10,000, which may be evidence of crimes such as drug dealing or money laundering. Unfortunately for Hovind, bankers also look out for structuring, which in itself is (contrary to what Hovind claimed) itself a federal crime, even if there's no underlying crime. So he did break the law, and he knows it.
He was also convicted of not withholding and submitting income taxes from his payroll. He's an all round tax cheat.
Broadly speaking, Hovind has a conspiracy-driven worldview and used many pseudo-legal arguments in court to claim that he did not have to pay taxes and the government has no jurisdiction over him: suggesting he is at least informally aligned with the so-called "sovereign citizen" movement. His wife was a co-conspirator, and they were divorced while he was in jail. He then also declared the traditional understanding of marriage illegitimate and got involved in one or two common-law marriages--even though Alabama, where he was living at the time, did not recognize common-law marriage. He also served more time for domestic abuse.
In other words, he's a piece of work.