Murphy became Neil Lennon's fourth signing as Celtic manager on Friday afternoon and the 27-year-old immediately promised his new boss he will score goals.
"We want to win, that's the main objective here," he said.
"I also want to stake a claim to be first choice striker, that's my first aim.
"It's going to be hard because there are some good strikers here but that's the first thing I need to do, make sure the manager wants me to be his number one.
"That's what I've come here to hopefully achieve.
"I just want to get into the team as quickly as possible.
"It's going to be hard work but I think if I put in the work and the effort - which I will do - hopefully I can start every game and play a big part in winning the title.
"I've been used as a left-midfielder quite a lot in my career, which is not my position, it's a centre-forward.
"I know, if given the chance to play as a striker and a run of games, I can score goals, especially in a team like Celtic who will be attacking a lot."
Murphy spent the second half of last season on loan at Ipswich and admits it was not a difficult decision to quit Sunderland for Celtic.
He said: "Because of the fact that I wasn't playing and featuring in the manager's plans, it was an easy decision to leave.
"But I had some great times there and I'd like to say thanks to everyone involved there and the fans.
"A lot of my family support Celtic and they are die-hard fans.
"I supported them as a boy and grew up knowing about the club and what it has achieved.
"As soon as I heard it was concrete that they wanted me, it was an automatic choice."
Murphy now hopes to make his competitive debut in Celtic's Champions League third round qualifier, after they were paired with Portuguese side Braga in the draw earlier today.
"I hope I can be involved," he said.
"The Champions League draw is a tricky game and I don't know much about them. But I think they came second in the Portuguese league this year so it will be a tough game."
Portuguese Liga runners-up Braga are making their debut in the competition and sporting director Fernando Couto, the former Barcelona and Portugal defender, admits they have a tough tie.
"It's a difficult opponent, from the possible ones perhaps the most difficult," Couto said.
"But we are now at a very high level and all the teams at this stage are big teams.
"It's a great opponent from a very tough league, but we have our weapons. If we want to be among the best we must beat these kind of teams.
"We are going to play in a very difficult stadium but I think we have a chance."
Meanwhile, goalkeeper Artur Boruc, who yesterday completed his move to Fiorentina, paid tribute to Celtic after bringing his five-year spell in the east end of Glasgow to an end.
He said: "It has been a privilege to play for such a massive club like Celtic and the support that I have received has been amazing and made my time at the club a very special part of my career and my life.
"I would like to thank the club for their support and give the Celtic fans a special 'hail, hail!'.
"The club and the fans are unique and I will continue to take an interest and follow the progress of Celtic.
"I hope I can return as a spectator and a supporter in the future and I wish my successor the very best of luck."