Johnston's sentencing is scheduled for May 18. Her former lover Eric Naposki is scheduled to be sentenced for murder on the same day.
Nanette Johnston, who also goes by Nanette Packard, was accused of living off of her 50-year-old boyfriend, William McLaughlin. McLaughlin was a Newport Beach millionaire.
Johnston is accused of convincing her lover, former NFL linebacker Eric Naposki, to kill McLaughlin in his Newport Beach home in December 1994. Naposki was convicted in the fatal shoooting.
The prosecutor alleges Johnston provided Naposki with the keys to house and McLaughlin's schedule.
"She was obviously motivated by money. She was motivated by her relationship with Eric Naposki," said Orange County Senior Deputy District Attorney Matt Murphy on Monday..
McLaughlin was shot six times in his kitchen. His disabled son, who was home upstairs at the time, heard the shots and found his father's body and called 911.
"She had a $1 million life insurance policy on Bill McLaughlin, which of course because it's a life insurance policy is payable only upon his death," said Murphy.
Murphy said that a day before the murder, Johnston wrote a check for $250,000 from one of McLaughlin's accounts and deposited it in her account.
In 1995 Johnston was charged with grand theft for stealing close to $500,000 from McLaughlin's account before and after his murder. Johnston pleaded guilty and was sentenced to a year in jail.
The murder investigation went cold until it was reopened and charges were filed in 2009.
"We really miss him. We're so glad that justice has been served on his behalf," said Jenny McLaughlin, one of the victim's daughters, after Monday's verdict.
"It's a lot of closure for us and for many of us today," said Kimberly McLaughlin, one of the victim's daughters, on Monday. "Thanks to our system today's the day. She got what she deserved."