The former Leeds Rhinos and England rugby league captain arrived at AMT Headingley Stadium in the afternoon having run from York on the final leg of his 7 in 7: Together venture.
Sinfield, who also joined up with a 'Santa Dash' in Leeds on Sunday, has run seven ultramarathons of at least 28 miles - around 185 miles in total - over the past seven days across the UK and Republic of Ireland.
It was Sinfield's sixth endurance challenge, having been inspired by his former Rhinos team-mate Rob Burrow, who died in 2024 having lived with MND for four and a half years.
Sinfield addressed the crowd after arriving at Headingley, his home ground throughout his glittering rugby league career which included seven Super League titles.
He said: "To the MND community and the people we've met en route, all through the last week, all through the past five years, to everybody we've met - you're an absolutely beautiful community. We've got to keep fighting for the MND community."
Sinfield, 45, had initially set a fundraising target of £777,777 - in tribute to Burrow's former shirt number seven - for the challenge but exceeded that.
The latest figure means he has now raised more than £11million for MND charities.