The 29-year-old star began selling CDs and rapping at a radio station, when one of the DJs advised him to ''go out and holler'' at the 'Famous' hitmaker.
And Sean seized his chance when they came face-to-face in 2005, with Kanye consenting to listen to his rhymes, even though he was running late.
Sean recalled to Billboard: ''He told me I had 16 bars. I ended up rapping for 10 minutes and it changed my life.''
Sean - who signed to Kanye's GOOD Music in 2007 - credits attending the Detroit Waldorf School, which he found was ''real artistic'', with cultivating his songwriting skills.
He explained: ''It was a school that just specialised in being like in tune with yourself, expressing the artistic side of yourself, the poetic side. So, we did poetry. I was the only person in the school turning those poems into raps.''
The 'Bounce Back' hitmaker loves performing live for his fans, and is a particularly big fan of the festival scene.
He said: ''It's an energetic exchange of people who got love for you, people who know every single word.
''That's the greatest honor any artist can have is to share that.''
And Sean loves ''every single one'' of his ''beautiful'' fans.
He gushed: ''My fan base is G'd up. You know, they downtown. They think they bosses.
''They're people who got my back no matter what. They're beautiful people, and I love every single one.''
Meanwhile, Sean recently revealed his favourite verse he features on - but admitted he loves all his musical contributions.
He said: ''That 'Detroit vs. Everybody' verse. That was a fire one. I remember that I didn't have any time hardly to do that and I somehow knocked it out in an hour.
''Every verse I do - it's not for everybody, but for me, I love it.
''Every time I do a verse, I feel like it's better than the last one.''