Prosecutors in Houston say 73-year-old Joe B. Phillips entered the pleas Tuesday.
Phillips was a court-appointed guardian or Department of Veterans Affairs-approved fiduciary for some veterans. Investigators didn't immediately say how much money was involved.
Phillips pleaded guilty to conspiracy to make false statements, misappropriation by a fiduciary and signing a false income tax return. He faces up to three years in prison for tax fraud and five years on the other counts.
His wife and assistant, 72-year-old Dorothy Phillips, in April pleaded guilty to conspiracy and making a false statement on an income tax return.
Phillips says his wife gambled extensively at Louisiana casinos from 2003 to 2007.