This year is shaping up to be a pivotal one for CSL, one of corporate Australia's few international successes and a star stock of last year.

By the year's end, CSL will not be led by Brian McNamee, one of the country's longest serving and most lauded chief executives.

Rather, Paul Perreault will take over the reins at the $26.7 billion blood plasma and vaccine company - from the streets of Philadelphia.

Although Perreault is the president of the company's chief money-spinning business, CSL Behring, the 55-year-old American is largely an unknown quantity in Australia, where retail shareholders comprise about 30 per cent of CSL's register.

Here are some vitals: Perreault has a degree in psychology and has spent three decades in the healthcare industry.

Married with children, he joined CSL in 2004 as part of its acquisition of Aventis Behring and, in July 2011, took over as president of CSL Behring - the blood plasma subsidiary that comprises the bulk of CSL's more than $US4.6 billion ($4.4 billion) in annual revenues.

UBS analyst Andrew Goodsall, recently rated Australia's top healthcare and biotech analyst, said that Perreault's ascension was not a surprise.

''He was running the division that was responsible for the lion's share of revenue, so it wasn't much of a stretch to think he could run the company,'' Goodsall said.

He said Perreault presented well, was well-respected in the industry and was ''very commercially focused''. The company also stresses his commercialisation and operational experience.

McNamee told BusinessDay his successor was a ''straightforward'' person. He said he and Perreault have similarities: they are about the same age, they have been married a similar amount of time, they enjoy golf and they're family-minded.

''We get on incredibly well,'' McNamee said, adding ''I expect to catch up with him'' after handing over the reins.

Under McNamee's leadership, CSL made two bumper acquisitions - the Red Cross's blood plasma business ZLB in 2000 and the US blood products group Aventis Behring.

Plans for a third, the $US3.1 billion purchase of US-based rival Talecris, were thwarted by a US regulator that noted a combined CSL and Talecris would have 80 per cent of the US market for blood plasma products.

The regulator accused CSL and rivals of focusing on ''preventing oversupply of IVIG [intravenous immunoglobulin] and plasma'' and developing ''sophisticated oligopoly models to estimate and predict changes in supply and demand'' - allegations CSL strongly rejected.

The regulator's finding triggered price-fixing lawsuits from medical practices and hospitals in the US. A CSL spokeswoman said this week that legal action was continuing.

CSL's focus now is on organic growth. Broker JP Morgan, after CSL's briefing last month, said ''progress across all aspects of CSL's R&D [research and development] pipeline was notable with a consistent timeline of launch dates (across new geographies, novel indications and new products) expected over the next five years''.

Goodsall said the recombinant haemophilia business had huge potential for CSL and its incoming CEO. ''He's the right guy for the right time,'' he said. ''If they get it right, it'll be transformational.''

The appointment of its first CEO to be based overseas raises the question of whether CSL will weaken links to its home town of Melbourne, where much of its research and development takes place.

Eighty-nine per cent of CSL's sales in the 2012 financial year came from operations outside of Australia and 83 per cent of its 10,515 employees were outside Australia. The company is shifting to reporting in US dollars this year.

McNamee said growth outside Australia would exceed growth at home, regardless of who led.

Last year, McNamee declared CSL was in its best ever shape; indeed, its shares ended the year 68 per cent higher - the best performance by a top 20 company - as it upgraded its profit guidance and investors digested yet another share buyback.

But some analysts say the momentum cannot be maintained.

''While CSL's market position shows no sign of being weakened, Baxter's return to full capacity and any softening in demand … mean earnings growth in FY14 and beyond will likely be more subdued,'' Deutsche Bank said in late November.

The good news for Perreault is he can look forward to a hefty pay rise when he takes over the top job in July. For the 2012 fiscal year, Perreault took home just over $2 million; McNamee was paid $7.69 million, including a $2 million cash bonus.