Mr Lesh is said to have made the donation to the campaign “Help Christine Blasey Ford” on Sunday 23 September, before Ms Ford testified to the US Senate Judiciary Committee over allegations that Supreme Court nominee Brett Kavanaugh sexually assaulted her at a party when she was 15 years old.
A representative for the musician, who was a founding member of the acclaimed American rock band, confirmed the donation to Rolling Stone but declined to provide further comment. Lesh did not initially publicise his donation.
The “Help Christine Blasey Ford” campaign is one of two GoFundMe accounts which have raised over $700,000 collectively to cover security and legal costs for Ms Ford and her family.
In 11 days, “Help Christine Blasey Ford” raised $528,475 before it stopped accepting contributions, while “Cover Dr Blasey’s security costs” raised $209,987. Both campaigns will transfer donations directly to the Ford family.
Ms Ford became a household name when she went public with allegations Mr Kavanaugh sexually assaulted her when they were both teenagers. Following her allegations, two other women, Deborah Ramirez and Julie Swetnick, have come forward with separate allegations of sexual misconduct by him.
Both Ms Ford and Mr Kavanaugh, who denies all the allegations, testified on Thursday during a heated eight-hour hearing.
On Friday, the Senate Judiciary Committee voted 11-10 to advance Mr Kavanaugh’s nomination to a full Senate vote.
After Republican Senator Jeff Flake supported the vote on the condition of a delay to allow the claims to be investigated, President Donald Trump ordered a week-long FBI investigation into sexual assault allegations against Mr Kavanaugh.
Lesh has also been active in support of other political and social causes recently.
Earlier this month, he performed at a benefit concert for HeadCount, a non-profit organisation which works to promote voter registration and participation in democracy.
At the vigil, he said: “I’m feeling such rage right now, such anguish and grief thinking about these brave spirits cut off before their time.
“We cannot allow this. Who are we if we cannot protect our children? Who are we if we don’t stand up, raise our voices, demand to be heard?”