Few details have been released to FOX6 News at this time.
In a statement, Abele said: "I appreciate the hard work Frank has done for Milwaukee County, and I wish him well."
Busalacchi had the top transportation job under Governor Jim Doyle and was appointed County Transportation Director about a year ago.
FOX6 News reached out to Busalacchi Wednesday evening but haven't yet received any response.
This news comes after County Executive Abele announced the firing of Milwaukee County Parks Director Sue Black. At this point, it is unclear whether Busalacchi was fired or left on his own accord.
Wednesday's news came as a surprise to many, including Milwaukee County supervisors.
"(Abele) may be getting a little bit of a reputation as an ax man but he has to be comfortable with the people he's working with, and I don't know the circumstances behind it," County Supervisor Joe Sanfelippo said.
Monitor FOX6 News and FOX6Now.com for updates on this developing story.