Keating was a law student in the States Attorney's Office for Baltimore City in 1967 and 1968 and was appointed an Assistant State's Attorney in December of 1969 when he passed the Bar. A mere four weeks later, he successfully prosecuted a first-degree murder case in front of a jury. Before he resigned in 1973, he was a Chief Prosecutor and personally handled 70 capital cases.
He was appointed an assistant public defender for Baltimore City a month later in 1973 assigned to represent individuals charged with stranger-to-stranger crimes of violence. Keating remained in that position until 1978. In that time he was involved in many major cases in Baltimore City and won acquittals in over fifty percent of his jury trials.
In the summer of 1978, Keating resigned his position in order to seek the Democratic nomination for State's Attorney in Baltimore City. He was endorsed by several local papers. The City Paper said, "...although only 34, Keating may know more about Baltimore's criminal justice system than anyone else. He's played key roles both as boy wonder chief prosecutor and the city's best-known public defender."
The Sun, in its endorsement, said, "In nine years as a prosecutor and a defense counsel, he has built an excellent reputation as a trial lawyer. He is thoroughly familiar with the criminal justice system.... Mr. Keating's record suggests he would do all in his power to see that justice in Baltimore was racially blind.... The Sun urges his nomination."
I was not successful in the election but, I was appointed Chief Counsel of the Medicaid Fraud Control Unit in the Attorney General's Office in 1979 and remained in that capacity prosecuting white collar crime until 1981 when he resigned to commence a private practice. He has been a private practitioner since then.
In the intervening years, he has represented hundreds of individuals in both federal and state court in both death penalty cases and relatively petty matters.
In 1981, he represented an accountant during a ten-week death penalty murder trial ,which to this date is still the longest murder trial in the State.
In 1985 in another capital case, Alan Murrel, the Public Defender for the State of Maryland requested Keating to represent an inmate serving life for murder in the alleged execution of a penitentiary guard. The trial lasted five weeks, and he was successful in saving this inmate's life.
Keating has appeared in serious criminal cases in twenty of the state's 24 local subdivisions. He as been a success and failure at the District, Circuit, and Appellate Court levels. For several years he was on the faculty of the Maryland Institute for Continuing Professional Education of Lawyers and has been a guest lecturer at law schools and other institutions.