A secret millionaire who disguised his wealth by wearing holey clothes and living a modest lifestyle has left a fortune worth $187.6 million to three charities in Washington state.

Jack MacDonald rode the bus and lived in an one bedroom apartment in Washington before he died at age 98 in September. His family says few people outside his immediate family knew he was wealthy.

"Our family has lived with the 'secret' of Jack's generous fortune for more than 40 years, all while being amazed at his frugal lifestyle and modest demeanor," said Regen Dennis, MacDonald's stepdaughter according to ABC News. "He was quirky and eccentric in many ways, and always stayed true to himself by acting on his convictions to do the most good with his wealth."

MacDonald left his fortune to Seattle Children's Hospital, where his mother worked as a volunteer, his alma mater University of Washington School of Law and the Salvation Army.

Doug Picha, the president of the Seattle Children's Hospital Foundation and MacDonald's longtime friend, said MacDonald never showed off his wealth. "I mean he loved a good deal, he clipped coupons and his shirt was maybe just a little tattered," said Picha.

Picha said MacDonald prided himself on "shepherding" the money from his family inheritance through the stock market so that it would be used for charities after his death.

"I think he just really enjoyed the fact that all of this wealth would be transferred onto those three charities," said Picha. "I think he felt he was a steward of [his parents'] funds."

He had no biological children of his own and his wife, whom he married in 1971, died in 1999.  Before he retired he worked as an attorney for three decades, however, he was able to amass his wealth by investing money he inherited from his parents, who owned MacDonald Meat Co. in Seattle, reports the Daily Mail.

His stepdaughter, Regan Dennis, said he was had a knack for investing in good stock.

"He didn't trust a lot of other people to do his research," she said. "He directed what he wanted [to be] bought, and he really knew what he wanted."