The appointments were by 5-0 votes, with Councilman Dennis Obeldobel absent. The men were then sworn in by District Judge Richard King.
The mayor's position opened on July 18 when Jeff Repasky announced his resignation after five years as mayor because he and his family are moving outside the borough. Mr. Cassidy became acting mayor while remaining president of council.
The lifelong borough resident was appointed mayor on his 54th birthday. He is a 40-year fire department member whose father and uncle were Mt. Oliver police officers.
Growing up in a public safety conscious family, and having worked with EMS, he said "I believe I can carry on the tradition of public safety as the top priority."
He also amassed knowledge of the borough and its everyday operations during his 12 years on council.
Mr. Cassidy is employed as a general foreman at Worldwide Refractories in Tarentum.
He plans to set up a "hotline" and email addressas Mr. Repasky had done in the past.
Mr. McGough assumed the seat previously held by Billie Michener. It was vacated by council in May after members accused her of missing too many meetings. She was appointed back into the seat after being the leading vote getter in the May primary election, but never accepted the appointment.
He was motivated to run for office while observing the borough's decline from a once-thriving community. He wants to help revitalize the business district and clean up the neighborhood.
Mr. Sains, 47, grew up in St. Clair Village. He has lived in the borough the past five years after residing there earlier for three years.
He is a senior warehouse man for Guardian Storage Solutions at its main site in Shadyside. Mr. Sains plans to be an advocate for youth, diversity, and seniors.
Both men were also winners in the May primary election.
Mr. Malloy, 67, said he plans to do some things differently as council president than did Mr. Cassidy. He was a councilman for 14 years beginning in the 1980s, and returned to council a few years ago.
His previous executive experience was as president of the Window Cleaners Local 16.
After the new council was seated, Mr. Malloy announced the new chairpersons and members of various committees.
The chairpersons are: Mr. McGough, Public Works; Mr. Sains, Economic Development/Planning/Zoning; John Smith, Recreation/Utilities/Ordinances; Christine Brendel, Administration and Related Office Equipment/Finance; Mr. Farneth, Public Safety/Risk Management.
In other business, Mr. Farneth reiterated his call for the borough to cut very high grass at a Margaret St. residence. Although the borough does not as standard practice cut residential lawns, the grass is so high it may be concealing mice and rats, making it a hazard to the surrounding homes.
He said he has received numerous complaints about the condition of the property.
Mr. Malloy read a resignation letter, effective July 24, from part-time police Officer Christopher J. Kertis, who accepted a new job with the city police department.