Black is the current Baby of the House as the youngest member in the House of Commons of the United Kingdom. When elected in May 2015, she was 20 years and 237 days old, making her the youngest MP elected to the House of Commons of the United Kingdom since at least the Reform Act of 1832.
Along with other LGBT MPs from the SNP, she expressed her support for same-sex marriage prior to the referendum in Ireland. Asked about her decision to "come out," she replied "I've never been in."
She is a supporter and season-ticket holder of Partick Thistle. She plays the piano, as was revealed in a Channel 4 News interview with Jon Snow, on 18 September 2015, during which she played theme music from the film Titanic.