Oloff Stevensen van Cortlandt was born in the Netherlands in 1600 and later became a soldier in the service of the West India Company. In 1637, he sailed from Holland in the ship the Hearing (Herring), with the newly appointed New Netherland Director Willem Kieft. The ship wintered in Bermuda and reached New Amsterdam on March 28, 1638 whereupon Director Kieft appointed Oloff Stevensen van Cortlandt as Commissary of Cargoes. Later he held the offices of Keeper of the Public Stores and Treasurer.
In 1645, van Cortlandt was selected as a member of the Eight Men. In 1649 he was appointed colonel of the Burgher Guard, and later that year, he was selected as a member of the Nine Men. Although he was a signatory to the Great Remonstrance of New Netherland, he would not deny his friendship with Director Kieft and wrote, beside his signature on the Remonstrance "Under protest; obliged to sign as to the Heer Kieft's administration." Oloff Stevensen van Cortlandt was elected Schepen of the City in 1654, and when the Court of Burgomasters and Schepens was established the following February, he took his seat on the Court. He was appointed paymaster of moneys ordered to be raised for the defense of the city of New Amsterdam and on February 2, 1655, he was appointed one of the two Burgomasters, a position he held in 1656-59, 1662-63 and again in 1665. Oloff Stevensent van Cortlandt was appointed by Director-General Stuyvesant to the Commission to resolve the Connecticut boundary dispute in 1663, and to a Commission to settle Captain John Scott's claim to Long Island in 1664. When New Netherland was captured by the English in 1664, Van Cortlandt was appointed by Director-General Stuyvesant to the Commission to negotiate the terms of surrender.
On February 2, 1665, Van Cortlandt took the oath of allegiance to the English Crown and in June of that year, when Governor Richard Nicolls abolished the Dutch form of government for the city of New York and established an English municipality (mayor, aldermen, and sheriff), Van Cortlandt was appointed one of the aldermen, a position he held until August 1668, and held again in the year 1670. On several occasions during the time he was alderman, he was acting-mayor of New York and in the minutes of the City Court he is styled "Deputy Mayor." Van Cortlandt also served as a Commissioner in the administrations of Governors Nicolls, Lovelace, and Dongan, and in 1673, was chosen the trustee to settle Governor Francis Lovelace's estate.
Oloff van Cortlandt lived on Brouwer Straat (now Stone Street) where he owned a successful brewery and became a wealthy man. He died in New York on April 4, 1684.