Bielaski was born in Poland, and in 1831 took part in the armed rebellion against the Russian Empire known as the November Uprising. After the failure of the rebellion, he was exiled to France, later immigrating to the United States. In 1837 he became an engineer in Illinois, where he got married and became acquainted with Abraham Lincoln. Bielaski moved to Washington, D.C. to work for the General Land Office, working his way to principal draftsman in 1853.
When the Civil War began, Bielaski offered his services to Lincoln. Lincoln then appointed him with the rank of captain as aide-de-camp to General John McClernand. Bielaski was killed on November 7, 1861 in the Battle of Belmont.
Bielaski had a son, Oscar Bielaski, who went on to become the first Polish-American baseball player for Major League Baseball. Bielaski's grandson A. Bruce Bielaski was the second director of the Bureau of Investigation (now the Federal Bureau of Investigation).
- Hughes, Nathaniel Cheairs (1991). The Battle of Belmont: Grant Strikes South. Chapel Hill, North Carolina, United States: UNC Press. ISBN 0807819689. http://books.google.com/books?id=GhgpaRAHJs0C. Retrieved 2008-03-17.
- Kiper, Richard L (1999). Major General John Alexander McClernand: Politician in Uniform. Kent, Ohio, United States: Kent State University Press. ISBN 0873386361. http://books.google.com/books?id=Cc4qNHKrNY8C. Retrieved 2008-03-17.