A Fischer-Tropsch catalyst, useful for conversion of synthesis gas to olefins, is prepared from a catalyst precursor composition including iron oxide and an alkali metal on a substantially inert support, and then treated by a process including as ordered steps (1) reduction in a hydrogen-containing atmosphere at a pressure of 0.1 to 1 M Pa and a temperature from 280° C. to 450° C.; (2) carburization in a carbon monoxide-containing atmosphere at a pressure from 0.1 to 1 M Pa and a temperature from 200° C. to less than 340° C.; and (3) conditioning in a hydrogen- and carbon monoxide-containing atmosphere at a pressure from 0.1 to 2 MPa and a temperature from 280° C. to 340° C. The resulting catalyst exhibits at least one improvement selected from (1) increased overall activity; (2) reduced break-in time; (3) slowed rate of deactivation; and (4) increased time to onset of deactivation; when compared to an otherwise identical catalyst precursor composition treated by one or some, but not all, of the given steps and/or under different conditions.