Born near Russellville, Kentucky, he attended the country schools and Lebanon Academy in Logan County, Kentucky. Later, he studied law, was admitted to the bar, and commenced practice in Elkton, Kentucky in 1827. He also engaged in agricultural pursuits.
McLean was a member of the Kentucky House of Representatives in 1837 and was also elected as a Whig to the Thirty-first Congress (March 4, 1849 - March 3, 1851). After leaving Congress, he resumed the practice of law and also engaged in agricultural pursuits. He moved to Andrew County, Missouri in 1860 and engaged in farming until 1865. Later, he relocated to Greencastle, Indiana in 1865 in which city he died in 1881. He was buried in Forest Hill Cemetery in Greencastle.