This looks really nice already, Kumiko! I have a few suggestions that might make it sound a bit more natural. Don't be afraid to use Mr. XXX's name throughout the profile, to make sure it's clear who did what, and really cement that it was Mr. XXX who did all the amazing things!
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Mr. XXX is the founder and the president of ZZZZZ Inc.
(often the first "the" can stand in for both positions when writing about jobs.)
Before starting his career as an independent contractor, Mr. XXXhe was the manager and the senior consultant of a professional consulting team at an IT outsourcing company (A corporation), who was specialized in business process design & improvement and consulting sales.
(It depends on the audience the profile is targed at, but when writing business profiles in English you can often assume the reader knows what kind of company you are talking about. For example, I wouldn't write ".. at the internet services company Google", I would just write ".. at Google".
Also, when you describe what the team did, you can use the present tense, as the team is presumably still doing the same thing, even after Mr. XXX left.)
Mr. XXXHe joined the human resource service company (B corporation) as a (YYY - you should give the name of his role) in 1997 and gained wide experience inof setting up new business and operation systems from scratch, including outbound call centers, technical support centers, and network management centers, etc. One of his most outstanding achievements was to establish the network monitoring service company (C corporation), a network monitoring service company, for (customer X). (C corporation) was (customer X)'s joint venture company with major trading companies (D corporation) and (E corporation). Mr. XXXHe(Use the name so it's clear it wasn't customer X) fully contributed to the design of its(C corporation)'s (use the name to make it less ambiguous about which company) business scheme, organization and operation systems.
(etc is implied when you say "including", so you can do a regular list structure. So "a, b, c, etc." has the same meaning as "including a, b and c"
I don't have a good reason for rearranging the sentence around C corporation other than it feels more natural to me...)
The IT outsourcing company (A corporation) was also one of the companies Mr. XXXhe contributed to as a board member from its inception(to start up and succeed). The company’s most strongest point was (a specific service name), which Mr. XXXhe developed and implemented inthrough(I think what you're trying to say is the thing Mr. XXX developed consisted of outsourcing projects?) outsourcing projects. He created over 300 proposals to customers, which resulted in more than half of the contracts the company made. With thehis wealth of experience and knowledge, Mr. XXXhe founded ZZZZZ inc. in 2004.
("to start up and succeed" sounds a bit strange. I think what you're saying is that Mr. XXX was on A corporation's board right from the beginning. If A corporation still exists, it's implied that the company was started up successfully)
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I hope these corrections and explanations makes some sense to you!
