A Missouri hospital administrator who began his health career as a clinical psychologist will replace Michael Means as the president and CEO of Health First. Health First's Board of Directors picked Steven P. Johnson, 56, to take over from Means, who founded Health First in 1995 and has been its only president/CEO. Means is retiring at the end of the year. Johnson is the president of hospital operations for SSM Health Care-St. Louis, part of the Catholic, not-for-profit health care system SSM Health Care.