Retired Gore police officer Mr McPhail (District-wide ward) is joined by plumber Nick Grant (Gore) and accountant Stewart MacDonell (Kaiwera-Waimumu) in the step up to council.
All sitting councillors were returned to office, and Gore District Mayor Tracy Hicks retained his seat unopposed for a sixth term.
Mataura Community Board also has a new member, after Steve (Boko) Dixon was elected.
Waikaka Valley resident Mr McPhail - whose most recent role was MPI regional recovery manager - said he was pleased with the mandate he received after placing first in the ward by nearly 600 votes, with 3014 votes.
"I've got the community backing. Now I need to step up."
Fellow newcomer Mr Grant said he was "excited" to have attained his electoral goal.
He polled fourth in the Gore ward, with 1387 votes.
"I've run my own business for 16 years, and you learn to think on the spot and plan ahead quickly. I like the facts, and I like to listen and learn."
Charlton resident Mr MacDonell replaces Graham Sharp in the Waimumu-Kaiwera ward, after he stood down.
He said he would focus initially on building relationships with new colleagues.
"There are some big challenges out there both for my ward and for council in general, so we need to work together to succeed."
Mr Hicks said he was looking forward to working with the new councillors.
"[They] bring a good mix of skills to the table."
The council will be sworn in on October 29.
As of Friday, 43.44% of voters (3809) had cast their vote.
The provisional figure was down on 2016, when 59.4% voted.
