Kerr was born in Vienna, Maryland, and taught school in Kennebec County. He moved to Crisfield, Maryland in 1880, and entered the employ of a lumber company as clerk. He then moved to Cambridge, Maryland in 1885, and was elected school examiner in August 1898, serving two years.

Kerr was elected as a Republican to Congress from the 1st Congressional district of Maryland to fill the vacancy caused by the resignation of John Walter Smith and served the remainder of Smith's term from November 6, 1900, to March 3, 1901, and was not a candidate for renomination in 1900. He returned to Cambridge, and became a traveling salesman. He died in Cambridge, and is interred in Christ Episcopal Church Cemetery.