Kay, 59, who was born Edinburgh to a Nigerian father and Scottish mother before she was adopted and brought up in Glasgow, reveals how she is still "deeply hurt" at being questioned about where she comes from.
She tells the programme, which will be broadcast on the BBC Scotland channel on Sunday, that she said she did not feel a proper sense of "belonging" to Scotland until she was appointed the country’s national poet, to succeed Liz Lochhead, five years ago.
Kay is the presenter of the hour-long documentary, Beyond Burns, which explores the impact and legacy of Scottish poets, past and present. Kay discuss her experiences of racism with another mixed-race Scottish writer, Hannah Lavery.
Kay tells Lavery: “As a young girl growing up in Bishopbriggs in Glasgow I felt quite isolated and writing was my companion. I was a victim of a lot of racism.
“A boy was expelled from my primary school for making up sweets made of mud, shoving them into my mouth and saying: ‘That’s what you should eat because you’re from mud hut. That was my earliest experience of repeated racism and that was at the age of seven.
“When I went to Stirling University there were fascists there then. They put up posters with my name on them saying: ‘Would you be seen with that Irish Catholic wog called Jackie Kay?’ For some reason they thought I was Irish Catholic.
“They put razor blades behind the posters so that anybody who tried to rip them down would also get their hands shredded.
"I remember responding by calling a public meeting. I thought the thing to do when people are trying to attack and silence you is not to be silenced if you can help it.”
The two poets discuss how their experiences of racism have inspired their work, including Kay’s piece “In My Country” and “Scotland, You’re No Mine,” by Lavery.
Kay said: “It (In My Country) was inspired by so many people stopping me and asking me where I’m from in my own country. They were so busy seeing my face that they wouldn’t hear my accent.
“If you live in a country that you feel you belong to you and that you love and people ask you where you are from all the time it is deeply hurtful.
Lavery tells Kay: “I was very vulnerable when I was writing it (Scotland, You’re No Mine) because it felt for a long time, especially growing up, like quite a complicated identity to own. It didn’t feel like one that really included me.
“I think the pain of being constantly questioned about your right to belong or right to claim an identity still feels very real and current.
“You being our Makar is a huge thing for women of colour, to see you representing us, representing poetry and words, and the way in which you embrace, and are hugely embraced by, this country.”
Kay says: “I’ve certainly found it’s been a long journey – it actually took me until I became the Makar – to feel that I properly belonged to my country.”