Ms Ullrich, who represented the West of Scotland region in the Scottish Parliament from 1999 to 2003, was a lifelong campaigner for independence.
It is understood that, as a close neighbour of a young Nicola Sturgeon, Ms Ullrich convinced the future First Minister to join the SNP.
Today on Twitter, Ms Sturgeon described her as one of “the most influential figures in my life”, adding that she was “devastated” by the news of her death.
“I’ll miss her so much,” the First Minister told followers. “My love to Grady, Shelley, John & her beloved grandkids.”
Deputy First Minister John Swinney said it was “very poignant” to be told of Ms Ullrich’s death by Ms Sturgeon, describing the former MSP - and SNP member for 55 years - as “a great friend and ally in good times and in tough times.”
“Love and condolences to her family,” his tweet concluded.
Ms Ullrich, who studied at Queen’s College Glasgow, was elected to the Scottish Parliament in 1999 after a 24-year-long career in social care.
Initially serving as the SNP’s shadow minister for Health and Community Care, she was appointed Chief Whip when John Swinney won the party leadership in 2000.
She stood down from the Scottish Parliament at the 2003 election, and ran unsuccessfully for the SNP presidency in 2005.
She is survived by a husband and two children, including BBC Scotland journalist Shelley Jofre.