Whelen was born into a family of Quakers, yet he joined the Patriot movement and raised a company of Associators which he commanded in the field; subsequently being disowned by the Society of Friends, he insisted it was right to oppose "lawless tyranny."

In 1794 he joined forces with Joseph Miller; their partnership soon expanded into shipping and at the end of the century also into an active trade in gunpowder with Revolutionary France, in spite of Whelen being a Federalist state senator.

He was, as "Agent for the removal of the Public Departments" in charge of physically moving the government from Philadelphia to Washington, D.C.[6][1][4][7] As a merchant, Whelen amassed substantial assets and he built an impressive home near Downingtown.

Yet, shortly before his death he suffered significant losses when the French government under Napoleon seized a number of his ships.

[8][4] The Defense Logistics Agency Troop Support Headquarters in Philadelphia is dedicated in honor of Israel Whelen.